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Sample records for events core damage

  1. Analysis of core damage frequency: Surry, Unit 1 internal events

    International Nuclear Information System (INIS)

    Bertucio, R.C.; Julius, J.A.; Cramond, W.R.

    1990-04-01

    This document contains the accident sequence analysis of internally initiated events for the Surry Nuclear Station, Unit 1. This is one of the five plant analyses conducted as part of the NUREG-1150 effort by the Nuclear Regulatory Commission. NUREG-1150 documents the risk of a selected group of nuclear power plants. The work performed and described here is an extensive of that published in November 1986 as NUREG/CR-4450, Volume 3. It addresses comments form numerous reviewers and significant changes to the plant systems and procedures made since the first report. The uncertainty analysis and presentation of results are also much improved. The context and detail of this report are directed toward PRA practitioners who need to know how the work was performed and the details for use in further studies. The mean core damage frequency at Surry was calculated to be 4.05-E-5 per year, with a 95% upper bound of 1.34E-4 and 5% lower bound of 6.8E-6 per year. Station blackout type accidents (loss of all AC power) were the largest contributors to the core damage frequency, accounting for approximately 68% of the total. The next type of dominant contributors were Loss of Coolant Accidents (LOCAs). These sequences account for 15% of core damage frequency. No other type of sequence accounts for more than 10% of core damage frequency. 49 refs., 52 figs., 70 tabs

  2. Analysis of core damage frequency, Surry, Unit 1 internal events appendices

    International Nuclear Information System (INIS)

    Bertucio, R.C.; Julius, J.A.; Cramond, W.R.

    1990-04-01

    This document contains the appendices for the accident sequence analyses of internally initiated events for the Surry Nuclear Station, Unit 1. This is one of the five plant analyses conducted as part of the NUREG-1150 effort by the Nuclear Regulatory Commission. NUREG-1150 documents the risk of a selected group of nuclear power plants. The work performed is an extensive reanalysis of that published in November 1986 as NUREG/CR-4450, Volume 3. It addresses comments from numerous reviewers and significant changes to the plant systems and procedures made since the first report. The uncertainty analysis and presentation of results are also much improved. The context and detail of this report are directed toward PRA practitioners who need to know how the work was performed and the details for use in further studies. The mean core damage frequency at Surry was calculated to be 4.0E-5 per year, with a 95% upper bound of 1.3E-4 and 5% lower bound of 6.8E-6 per year. Station blackout type accidents (loss of all AC power) were the largest contributors to the core damage frequency, accounting for approximately 68% of the total. The next type of dominant contributors were Loss of Coolant Accidents (LOCAs). These sequences account for 15% of core damage frequency. No other type of sequence accounts for more than 10% of core damage frequency

  3. Analysis of core damage frequency from internal events: Peach Bottom, Unit 2

    International Nuclear Information System (INIS)

    Kolaczkowski, A.M.; Lambright, J.A.; Ferrell, W.L.; Cathey, N.G.; Najafi, B.; Harper, F.T.

    1986-10-01

    This document contains the internal event initiated accident sequence analyses for Peach Bottom, Unit 2; one of the reference plants being examined as part of the NUREG-1150 effort by the Nuclear Regulatory Commission. NUREG-1150 will document the risk of a selected group of nuclear power plants. As part of that work, this report contains the overall core damage frequency estimate for Peach Bottom, Unit 2, and the accompanying plant damage state frequencies. Sensitivity and uncertainty analyses provided additional insights regarding the dominant contributors to the Peach Bottom core damage frequency estimate. The mean core damage frequency at Peach Bottom was calculated to be 8.2E-6. Station blackout type accidents (loss of all ac power) were found to dominate the overall results. Anticipated Transient Without Scram accidents were also found to be non-negligible contributors. The numerical results are largely driven by common mode failure probability estimates and to some extent, human error. Because of significant data and analysis uncertainties in these two areas (important, for instance, to the most dominant scenario in this study), it is recommended that the results of the uncertainty and sensitivity analyses be considered before any actions are taken based on this analysis

  4. Analysis of core damage frequency: Peach Bottom, Unit 2 internal events appendices

    International Nuclear Information System (INIS)

    Kolaczkowski, A.M.; Cramond, W.R.; Sype, T.T.; Maloney, K.J.; Wheeler, T.A.; Daniel, S.L.

    1989-08-01

    This document contains the appendices for the accident sequence analysis of internally initiated events for the Peach Bottom, Unit 2 Nuclear Power Plant. This is one of the five plant analyses conducted as part of the NUREG-1150 effort for the Nuclear Regulatory Commission. The work performed and described here is an extensive reanalysis of that published in October 1986 as NUREG/CR-4550, Volume 4. It addresses comments from numerous reviewers and significant changes to the plant systems and procedures made since the first report. The uncertainty analysis and presentation of results are also much improved, and considerable effort was expended on an improved analysis of loss of offsite power. The content and detail of this report is directed toward PRA practitioners who need to know how the work was done and the details for use in further studies. The mean core damage frequency is 4.5E-6 with 5% and 95% uncertainty bounds of 3.5E-7 and 1.3E-5, respectively. Station blackout type accidents (loss of all ac power) contributed about 46% of the core damage frequency with Anticipated Transient Without Scram (ATWS) accidents contributing another 42%. The numerical results are driven by loss of offsite power, transients with the power conversion system initially available operator errors, and mechanical failure to scram. 13 refs., 345 figs., 171 tabs

  5. Analysis of core damage frequency due to external events at the DOE [Department of Energy] N-Reactor

    International Nuclear Information System (INIS)

    Lambright, J.A.; Bohn, M.P.; Daniel, S.L.; Baxter, J.T.; Johnson, J.J.; Ravindra, M.K.; Hashimoto, P.O.; Mraz, M.J.; Tong, W.H.; Conoscente, J.P.; Brosseau, D.A.

    1990-11-01

    A complete external events probabilistic risk assessment has been performed for the N-Reactor power plant, making full use of all insights gained during the past ten years' developments in risk assessment methodologies. A detailed screening analysis was performed which showed that all external events had negligible contribution to core damage frequency except fires, seismic events, and external flooding. A limited scope analysis of the external flooding risk indicated that it is not a major risk contributor. Detailed analyses of the fire and seismic risks resulted in total (mean) core damage frequencies of 1.96E-5 and 4.60E-05 per reactor year, respectively. Detailed uncertainty analyses were performed for both fire and seismic risks. These results show that the core damage frequency profile for these events is comparable to that found for existing commercial power plants if proposed fixes are completed as part of the restart program. 108 refs., 85 figs., 80 tabs

  6. Analysis of core damage frequency due to external events at the DOE (Department of Energy) N-Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lambright, J.A.; Bohn, M.P.; Daniel, S.L. (Sandia National Labs., Albuquerque, NM (USA)); Baxter, J.T. (Westinghouse Hanford Co., Richland, WA (USA)); Johnson, J.J.; Ravindra, M.K.; Hashimoto, P.O.; Mraz, M.J.; Tong, W.H.; Conoscente, J.P. (EQE, Inc., San Francisco, CA (USA)); Brosseau, D.A. (ERCE, Inc., Albuquerque, NM (USA))

    1990-11-01

    A complete external events probabilistic risk assessment has been performed for the N-Reactor power plant, making full use of all insights gained during the past ten years' developments in risk assessment methodologies. A detailed screening analysis was performed which showed that all external events had negligible contribution to core damage frequency except fires, seismic events, and external flooding. A limited scope analysis of the external flooding risk indicated that it is not a major risk contributor. Detailed analyses of the fire and seismic risks resulted in total (mean) core damage frequencies of 1.96E-5 and 4.60E-05 per reactor year, respectively. Detailed uncertainty analyses were performed for both fire and seismic risks. These results show that the core damage frequency profile for these events is comparable to that found for existing commercial power plants if proposed fixes are completed as part of the restart program. 108 refs., 85 figs., 80 tabs.

  7. Analysis of core damage frequency from internal events: Methodology guidelines: Volume 1

    International Nuclear Information System (INIS)

    Drouin, M.T.; Harper, F.T.; Camp, A.L.

    1987-09-01

    NUREG-1150 examines the risk to the public from a selected group of nuclear power plants. This report describes the methodology used to estimate the internal event core damage frequencies of four plants in support of NUREG-1150. In principle, this methodology is similar to methods used in past probabilistic risk assessments; however, based on past studies and using analysts that are experienced in these techniques, the analyses can be focused in certain areas. In this approach, only the most important systems and failure modes are modeled in detail. Further, the data and human reliability analyses are simplified, with emphasis on the most important components and human actions. Using these methods, an analysis can be completed in six to nine months using two to three full-time systems analysts and part-time personnel in other areas, such as data analysis and human reliability analysis. This is significantly faster and less costly than previous analyses and provides most of the insights that are obtained by the more costly studies. 82 refs., 35 figs., 27 tabs

  8. Review of the Shoreham Nuclear Power Station Probabilistic Risk Assessment: internal events and core damage frequency

    International Nuclear Information System (INIS)

    Ilberg, D.; Shiu, K.; Hanan, N.; Anavim, E.

    1985-11-01

    A review of the Probabilistic Risk Assessment of the Shoreham Nuclear Power Station was conducted with the broad objective of evaluating its risks in relation to those identified in the Reactor Safety Study (WASH-1400). The scope of the review was limited to the ''front end'' part, i.e., to the evaluation of the frequencies of states in which core damage may occur. Furthermore, the review considered only internally generated accidents, consistent with the scope of the PRA. The review included an assessment of the assumptions and methods used in the Shoreham study. It also encompassed a reevaluation of the main results within the scope and general methodological framework of the Shoreham PRA, including both qualitative and quantitative analyses of accident initiators, data bases, and accident sequences which result in initiation of core damage. Specific comparisons are given between the Shoreham study, the results of the present review, and the WASH-1400 BWR, for the core damage frequency. The effect of modeling uncertainties was considered by a limited sensitivity study so as to show how the results would change if other assumptions were made. This review provides an independently assessed point value estimate of core damage frequency and describes the major contributors, by frontline systems and by accident sequences. 17 figs., 81 tabs

  9. Analysis of core damage frequency from internal events: Surry, Unit 1

    International Nuclear Information System (INIS)

    Harper, F.T.

    1986-11-01

    This document contains the accident sequence analyses for Surry, Unit 1; one of the reference plants being examined as part of the NUREG-1150 effort by the Nuclear Regulatory Commission (NRC). NUREG-1150 will document the risk of a selected group of nuclear power plants. As part of that work, this report contains the overall core damage frequency estimate for Surry, Unit 1, and the accompanying plant damage state frequencies. Sensitivity and uncertainty analyses provide additional insights regarding the dominant contributors to the Surry core damage frequency estimate. The numerical results are driven to some degree by modeling assumptions and data selection for issues such as reactor coolant pump seal LOCAs, common cause failure probabilities, and plant response to station blackout and loss of electrical bust initiators. The sensitivity studies explore the impact of alternate theories and data on these issues

  10. Procedures for the external event core damage frequency analyses for NUREG-1150

    International Nuclear Information System (INIS)

    Bohn, M.P.; Lambright, J.A.

    1990-11-01

    This report presents methods which can be used to perform the assessment of risk due to external events at nuclear power plants. These methods were used to perform the external events risk assessments for the Surry and Peach Bottom nuclear power plants as part of the NRC-sponsored NUREG-1150 risk assessments. These methods apply to the full range of hazards such as earthquakes, fires, floods, etc. which are collectively known as external events. The methods described in this report have been developed under NRC sponsorship and represent, in many cases, both advancements and simplifications over techniques that have been used in past years. They also include the most up-to-date data bases on equipment seismic fragilities, fire occurrence frequencies and fire damageability thresholds. The methods described here are based on making full utilization of the power plant systems logic models developed in the internal events analyses. By making full use of the internal events models one obtains an external event analysis that is consistent both in nomenclature and in level of detail with the internal events analyses, and in addition, automatically includes all the appropriate random and tests/maintenance unavailabilities as appropriate. 50 refs., 9 figs., 11 tabs

  11. Review of the Oconee-3 probabilistic risk assessment: external events, core damage frequency. Volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Hanan, N.A.; Ilberg, D.; Xue, D.; Youngblood, R.; Reed, J.W.; McCann, M.; Talwani, T.; Wreathall, J.; Kurth, P.D.; Bandyopadhyay, K.

    1986-03-01

    A review of the Oconee-3 Probabilistic Risk Assessment (OPRA) was conducted with the broad objective of evaluating qualitatively and quantitatively (as much as possible) the OPRA assessment of the important sequences that are ''externally'' generated and lead to core damage. The review included a technical assessment of the assumptions and methods used in the OPRA within its stated objective and with the limited information available. Within this scope, BNL performed a detailed reevaluation of the accident sequences generated by internal floods and earthquakes and a less detailed review (in some cases a scoping review) for the accident sequences generated by fires, tornadoes, external floods, and aircraft impact. 12 refs., 24 figs., 31 tabs.

  12. Review of the Oconee-3 probabilistic risk assessment: external events, core damage frequency. Volume 2

    International Nuclear Information System (INIS)

    Hanan, N.A.; Ilberg, D.; Xue, D.

    1986-03-01

    A review of the Oconee-3 Probabilistic Risk Assessment (OPRA) was conducted with the broad objective of evaluating qualitatively and quantitatively (as much as possible) the OPRA assessment of the important sequences that are ''externally'' generated and lead to core damage. The review included a technical assessment of the assumptions and methods used in the OPRA within its stated objective and with the limited information available. Within this scope, BNL performed a detailed reevaluation of the accident sequences generated by internal floods and earthquakes and a less detailed review (in some cases a scoping review) for the accident sequences generated by fires, tornadoes, external floods, and aircraft impact. 12 refs., 24 figs., 31 tabs

  13. Ex-core fuel damage event at paks causes, consequences and lessons learned

    International Nuclear Information System (INIS)

    Bajsz, J.; Gado, J.

    2004-01-01

    On April 10, 2003 Paks NPP experienced a loss of decay-heat removal to 30 irradiated fuel assemblies undergoing a cleaning process in a fuel service pit near the unit 2 spent fuel pool. Following chemical cleaning of high decay-heat fuel, a delay in removing the cleaning vessel's lid left the cleaning system in such a condition that did not provide adequate cooling to the fuel. After several hours of the fuel being under-cooled, a steam bubble developed in the vessel, essentially uncovering the fuel. When the lid of the vessel was removed, the sudden introduction of cool water thermally shocked the fuel causing significant structural damage and a release of fission product gases to the reactor building. The paper will discuss the causes of the event as well as the contributing factors to it. Detailed information will be given about the planning and preparation of the recovery actions. The in-depth analyses of the consequences and lessons learned complete the lecture. (author)

  14. Core damage risk indicators

    International Nuclear Information System (INIS)

    Szikszai, T.

    1994-01-01

    The purpose of this document is to show a method for the fast recalculation of the PSA. To avoid the information loose, it is necessary to simplify the PSA models, or at least reorganize them. The method, introduced in this document, require that preparation, so we try to show, how to do that. This document is an introduction. This is the starting point of the work related to the development of the risk indicators. In the future, with the application of this method, we are going to show an everyday use of the PSA results to produce the indicators of the core damage risk. There are two different indicators of the plant safety performance, related to the core damage risk. The first is the core damage frequency indicator (CDFI), and the second is the core damage probability indicator (CDPI). Of course, we cannot describe all of the possible ways to use these indicators, rather we will try to introduce the requirements to establish such an indicator system and the calculation process

  15. Analysis of core damage frequency: Peach Bottom, Unit 2 internal events

    International Nuclear Information System (INIS)

    Kolaczkowski, A.M.; Cramond, W.R.; Sype, T.T.; Maloney, K.J.; Wheeler, T.A.; Daniel, S.L.

    1989-08-01

    This document contains the appendices for the accident sequence analysis of internally initiated events for the Peach Bottom, Unit 2 Nuclear Power Plant. This is one of the five plant analyses conducted as part of the NUREG-1150 effort for the Nuclear Regulatory Commission. The work performed and described here is an extensive reanalysis of that published in October 1986 as NUREG/CR-4550, Volume 4. It addresses comments from numerous reviewers and significant changes to the plant systems and procedures made since the first report. The uncertainty analysis and presentation of results are also much improved, and considerable effort was expended on an improved analysis of loss of offsite power. The content and detail of this report is directed toward PRA practitioners who need to know how the work was done and the details for use in further studies. 58 refs., 58 figs., 52 tabs

  16. Applicability of PRISM PRA Methodology to the Level II Probabilistic Safety Analysis of KALIMER-600 (I) (Core Damage Event Tree Analysis Part)

    International Nuclear Information System (INIS)

    Park, S. Y.; Kim, T. W.; Ha, K. S.; Lee, B. Y.

    2009-03-01

    The Korea Atomic Energy Research Institute (KAERI) has been developing liquid metal reactor (LMR) design technologies under a National Nuclear R and D Program. Nevertheless, there is no experience of the PSA domestically for a fast reactor with the metal fuel. Therefore, the objective of this study is to establish the methodologies of risk assessment for the reference design of KALIMER-600 reactor. An applicability of the PSA of the PRISM plant to the KALIMER-600 has been studied. The study is confined to a core damage event tree analysis which is a part of a level 2 PSA. Assuming that the accident types, which can be developed from level 1 PSA, are same as the PRISM PRA, core damage categories are defined and core damage event trees are developed for the KALIMER-600 reactor. Fission product release fractions of the core damage categories and branch probabilities of the core damage event trees are referred from the PRISM PRA temporarily. Plant specific data will be used during the detail analysis

  17. Estimation of core-damage frequency to evolutionary ALWR [advanced light water reactor] due to seismic initiating events: Task 4.3.3

    International Nuclear Information System (INIS)

    Brooks, R.D.; Harrison, D.G.; Summitt, R.L.

    1990-04-01

    The Electric Power Research Institute (EPRI) is presently developing a requirements document for the design of advanced light water reactors (ALWRs). One of the basic goals of the EPRI ALWR Requirements Document is that the core-damage frequency for an ALWR shall be less than 1.0E-5. To aid in this effort, the Department of Energy's Advanced Reactor Severe Accident Program (ARSAP) initiated a functional probabilistic risk assessment (PRA) to determine how effectively the evolutionary plant requirements contained in the existing EPRI Requirements Document assure that this safety goal will be met. This report develops an approximation of the core-damage frequency due to seismic events for both evolutionary plant designs (pressurized-water reactor (PWR) and boiling-water reactor(BWR)) as modeled in the corresponding functional PRAs. Component fragility values were taken directly form information which has been submitted for inclusion in Appendix A to Volume 1 of the EPRI Requirements Document. The results show a seismic core-damage frequency of 5.2E-6 for PWRS and 5.0E-6 for BWRs. Combined with the internal initiators from the functional PRAs, the overall core-damage frequencies are 6.0E-6 for the pwr and BWR, both of which satisfy the 1.0E-5 EPRI goal. In addition, site-specific considerations, such as more rigid components and less conservative fragility data and seismic hazard curves, may further reduce these frequencies. The effect of seismic events on structures are not addressed in this generic evaluation and should be addressed separately on a design-specific basis. 7 refs., 6 figs., 3 tabs

  18. Analysis of core damage frequency from internal events: Expert judgment elicitation. Part 1: Expert panel results. Part 2: Project staff results

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, T A; Cramond, W R [Sandia National Laboratories, Albuquerque, NM (United States); Hora, S C [University of Hawii at Hilo (United States); Unwin, S D [Brookhaven National Laboratory (United States)

    1989-04-01

    Quantitative modeling techniques have limitations as to the resolution of important issues in probabilistic risk assessment (PRA). Not all issues can be resolved via the existing set of methods such as fault trees, event trees, statistical analyses, data collection, and computer simulation. Therefore, an expert judgment process was developed to address issues perceived as important to risk in the NUREG-1150 analysis but which could not be resolved with existing techniques. This process was applied to several issues that could significantly affect the internal event core damage frequencies of the PRAs performed on six light water reactors. Detailed descriptions of these issues and the results of the expert judgment elicitation are reported here, as well as an explanation of the methodology used and the procedure followed in performing the overall elicitation task. The process is time-consuming and expensive. However, the results are very useful, and represent an improvement over the draft NUREG-1150 analysis in the areas of expert selection, elicitation training, issue selection and presentation, elicitation of judgment and aggregation of results. The results are presented in two parts. Part documents the expert panel elicitations, where the most important issues were presented to a panel of experts convened from throughout the nuclear power risk assessment community. Part 2 documents the process by which the project staff performed expert judgment on other important issues, using the project staff as panel members. (author)

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

    International Nuclear Information System (INIS)

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

    1994-07-01

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

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

    International Nuclear Information System (INIS)

    Lambright, J.; Yakle, J.

    1994-07-01

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

  1. Estimative of core damage frequency in IPEN's IEA-R1 research reactor (PSA level 1) due to the initiating event of loss of coolant caused by large rupture in the pipe of the primary circuit

    International Nuclear Information System (INIS)

    Hirata, Daniel Massami

    2009-01-01

    This work applies the methodology of probabilistic safety assessment level 1 to the research reactor IEA-R1 IPEN-CNEN/SP. Two categories of identified initiating events of accidents in the reactor are studied: loss of flow and loss of primary coolant. Among the initiating events, blockage of flow channel and loss of cooling fluid by major pipe rupture in the primary circuit are chosen for a detailed analysis. The event tree technique is used to analyze the evolution of the accident, including the actuation or the fail of actuation of the safety systems and the reactor damages. Using the fault tree the reliability of the following reactor safety systems is evaluated: reactor shutdown system, isolation of the reactor pool, emergency core cooling system (ECCS) and the electric system. Estimative for the frequency of damage to the reactor core and the probability of failure of the analyzed systems are calculated. The estimated values for the frequencies of core damage are within the expected margins and are of the same order of magnitude as those found for similar reactors. The reliability of the reactor shutdown system, isolation of the reactor pool and ECCS are satisfactory for the conditions these systems are required. However, for the electric system it is suggested an upgrade to increase its reliability. (author)

  2. Estimative of core damage frequency in IPEN'S IEA-R1 research reactor due to the initiating event of loss of coolant caused by large rupture in the pipe of the primary circuit

    International Nuclear Information System (INIS)

    Hirata, Daniel Massami; Sabundjian, Gaiane; Cabral, Eduardo Lobo Lustosa

    2009-01-01

    The National Commission of Nuclear Energy (CNEN), which is the Brazilian nuclear regulatory commission, imposes safety and licensing standards in order to ensure that the nuclear power plants operate in a safe way. For licensing a nuclear reactor one of the demands of CNEN is the simulation of some accidents and thermalhydraulic transients considered as design base to verify the integrity of the plant when submitted to adverse conditions. The accidents that must be simulated are those that present large probability to occur or those that can cause more serious consequences. According to the FSAR (Final Safety Analysis Report) the initiating event that can cause the largest damage in the core, of the IEA-R1 research reactor at IPEN-CNEN/SP, is the LOCA (Loss of Coolant Accident). The objective of this paper is estimate the frequency of the IEA-R1 core damage, caused by this initiating event. In this paper we analyze the accident evolution and performance of the systems which should mitigate this event: the Emergency Coolant Core System (ECCS) and the isolated pool system. They will be analyzed by means of the event tree. In this work the reliability of these systems are also quantified using the fault tree. (author)

  3. Drivers of flood damage on event level

    DEFF Research Database (Denmark)

    Kreibich, H.; Aerts, J. C. J. H.; Apel, H.

    2016-01-01

    Flood risk is dynamic and influenced by many processes related to hazard, exposure and vulnerability. Flood damage increased significantly over the past decades, however, resulting overall economic loss per event is an aggregated indicator and it is difficult to attribute causes to this increasing...... trend. Much has been learned about damaging processes during floods at the micro-scale, e.g. building level. However, little is known about the main factors determining the amount of flood damage on event level. Thus, we analyse and compare paired flood events, i.e. consecutive, similar damaging floods...... example are the 2002 and 2013 floods in the Elbe and Danube catchments in Germany. The 2002 flood caused the highest economic damage (EUR 11600 million) due to a natural hazard event in Germany. Damage was so high due to extreme flood hazard triggered by extreme precipitation and a high number...

  4. Precursors to potential severe core damage accidents. A status report, 1982--1983

    Energy Technology Data Exchange (ETDEWEB)

    Forester, J.A.; Mitchell, D.B.; Whitehead, D.W. [and others

    1997-04-01

    This study is a continuation of earlier work that evaluated 1969-1981 and 1984-1994 events affecting commercial light-water reactors. One-hundred nine operational events that affected 51 reactors during 1982 and 1983 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10{sup {minus}6}. These events were identified by first computer screening the 1982-83 licensee event reports from commercial light-water reactors to select events that could be precursors to core damage. Candidates underwent engineering evaluation that identified, analyzed, and documented the precursors. This report discusses the general rationale for the study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events.

  5. Precursors to potential severe core damage accidents. A status report, 1982--1983

    International Nuclear Information System (INIS)

    Forester, J.A.; Mitchell, D.B.; Whitehead, D.W.

    1997-04-01

    This study is a continuation of earlier work that evaluated 1969-1981 and 1984-1994 events affecting commercial light-water reactors. One-hundred nine operational events that affected 51 reactors during 1982 and 1983 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10 -6 . These events were identified by first computer screening the 1982-83 licensee event reports from commercial light-water reactors to select events that could be precursors to core damage. Candidates underwent engineering evaluation that identified, analyzed, and documented the precursors. This report discusses the general rationale for the study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events

  6. Station blackout core damage frequency in an advanced nuclear reactor

    International Nuclear Information System (INIS)

    Carvalho, Luiz Sergio de

    2004-01-01

    Even though nuclear reactors are provided with protection systems so that they can be automatically shut down in the event of a station blackout, the consequences of this event can be severe. This is because many safety systems that are needed for removing residual heat from the core and for maintaining containment integrity, in the majority of the nuclear power plants, are AC dependent. In order to minimize core damage frequency, advanced reactor concepts are being developed with safety systems that use natural forces. This work shows an improvement in the safety of a small nuclear power reactor provided by a passive core residual heat removal system. Station blackout core melt frequencies, with and without this system, are both calculated. The results are also compared with available data in the literature. (author)

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

    International Nuclear Information System (INIS)

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

    1994-08-01

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

  8. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1. Volume 5: Analysis of core damage frequency from seismic events during mid-loop operations

    International Nuclear Information System (INIS)

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

    1994-08-01

    In 1989 the US Nuclear Regulatory Commission (NRC) initiated an extensive program to examine carefully the potential risks during low-power and shutdown operations. The program included two parallel projects, one at Brookhaven National Laboratory studying a pressurized water reactor (Surry Unit 1) and the other at Sandia National Laboratories studying a boiling water reactor (Grand Gulf). Both the Brookhaven and Sandia projects have examined only accidents initiated by internal plant faults--so-called ''internal initiators.'' This project, which has explored the likelihood of seismic-initiated core damage accidents during refueling shutdown conditions, is complementary to the internal-initiator analyses at Brookhaven and Sandia. This report covers the seismic analysis at Surry Unit 1. All of the many systems modeling assumptions, component non-seismic failure rates, and human error rates that were used in the internal-initiator study at Surry have been adopted here, so that the results of the two studies can be as comparable as possible. Both the Brookhaven study and this study examine only two shutdown plant operating states (POSs) during refueling outages at Surry, called POS 6 and POS 10, which represent mid-loop operation before and after refueling, respectively. This analysis has been limited to work analogous to a level-1 seismic PRA, in which estimates have been developed for the core-damage frequency from seismic events during POSs 6 and 10. The results of the analysis are that the core-damage frequency of earthquake-initiated accidents during refueling outages in POS 6 and POS 10 is found to be low in absolute terms, less than 10 -6 /year

  9. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit-1: Analysis of core damage frequency from internal events during mid-loop operations. Appendix I, Volume 2, Part 5

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.; Musicki, Z.; Kohut, P.; Yang, J.; Bozoki, G.; Hsu, C.J.; Diamond, D.J. [Brookhaven National Lab., Upton, NY (United States); Bley, D.; Johnson, D. [PLG Inc., Newport Beach, CA (United States); Holmes, B. [AEA Technology, Dorset (United Kingdom)] [and others

    1994-06-01

    Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent studies and operational experience have implied that accidents during low power and shutdown could be significant contributors to risk. During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Lab. (BNL) and Sandia National Labs. (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this volume of the report is to document the approach utilized in the level-1 internal events PRA for the Surry plant, and discuss the results obtained. A phased approach was used in the level-1 program. In phase 1, which was completed in Fall 1991, a coarse screening analysis examining accidents initiated by internal events (including internal fire and flood) was performed for all plant operational states (POSs). The objective of the phase 1 study was to identify potential vulnerable plant configurations, to characterize (on a high, medium, or low basis) the potential core damage accident scenarios, and to provide a foundation for a detailed phase 2 analysis.

  10. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit-1: Analysis of core damage frequency from internal events during mid-loop operations. Appendix I, Volume 2, Part 5

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.; Yang, J.; Bozoki, G.; Hsu, C.J.; Diamond, D.J.; Bley, D.; Johnson, D.; Holmes, B.

    1994-06-01

    Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent studies and operational experience have implied that accidents during low power and shutdown could be significant contributors to risk. During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Lab. (BNL) and Sandia National Labs. (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this volume of the report is to document the approach utilized in the level-1 internal events PRA for the Surry plant, and discuss the results obtained. A phased approach was used in the level-1 program. In phase 1, which was completed in Fall 1991, a coarse screening analysis examining accidents initiated by internal events (including internal fire and flood) was performed for all plant operational states (POSs). The objective of the phase 1 study was to identify potential vulnerable plant configurations, to characterize (on a high, medium, or low basis) the potential core damage accident scenarios, and to provide a foundation for a detailed phase 2 analysis

  11. Precursors to potential severe core damage accidents: 1992, A status report

    International Nuclear Information System (INIS)

    Cox, D.F.; Cletcher, J.W.; Copinger, D.A.; Cross-Dial, A.E.; Morris, R.H.; Vanden Heuvel, L.N.; Dolan, B.W.; Jansen, J.M.; Minarick, J.W.; Lau, W.; Salyer, W.D.

    1993-12-01

    Twenty-seven operational events with conditional probabilities of subsequent severe core damage of 1.0 x 10E-06 or higher occurring at commercial light-water reactors during 1992 are considered to be precursors to potential core damage. These are described along with associated significance estimates, categorization, and subsequent analyses. The report discusses (1) the general rationale for this study, (2) the selection and documentation of events as precursors, (3) the estimation and use of conditional probabilities of subsequent severe core damage to rank precursor events, and (4) the plant models used in the analysis process

  12. Status of the TMI-2 core: a review of damage assessments

    International Nuclear Information System (INIS)

    Croucher, D.W.

    1981-01-01

    Assessments of the damage within the core of the Three Mile Island Unit 2 reactor, performed by reconstructing the transient thermal-hydraulic sequence of events, estimating the amount of hydrogen generation, and evaluating the amount of fission products released, are reviewed and summarized. Minimum and maximum bounds of damage to the core are identified

  13. Drivers of flood damage on event level

    DEFF Research Database (Denmark)

    Kreibich, H.; Aerts, J. C. J. H.; Apel, H.

    2016-01-01

    example are the 2002 and 2013 floods in the Elbe and Danube catchments in Germany. The 2002 flood caused the highest economic damage (EUR 11600 million) due to a natural hazard event in Germany. Damage was so high due to extreme flood hazard triggered by extreme precipitation and a high number......-level mitigation measures, 3) more effective early warning and improved coordination of disaster response and 4) a more targeted maintenance of flood defence systems and their deliberate relocation. Thus, despite higher hydrological severity damage due to the 2013 flood was significantly lower than in 2002. In our...

  14. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations. Appendix E (Sections E.9-E.16), Volume 2, Part 3B

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.; Musicki, Z.; Kohut, P.; Yang, J.; Bozoki, G.; Hsu, C.J.; Diamond, D.J.; Wong, S.M. [Brookhaven National Lab., Upton, NY (United States); Bley, D.; Johnson, D. [PLG Inc., Newport Beach, CA (United States)] [and others

    1994-06-01

    Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent studies and operational experience have implied that accidents during low power and shutdown could be significant contributors to risk. Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The scope of the program includes that of a level-3 PRA. In phase 2, mid-loop operation was selected as the plant configuration to be analyzed based on the results of the phase 1 study. The objective of the phase 2 study is to perform a detailed analysis of the potential accident scenarios that may occur during mid-loop operation, and compare the results with those of NUREG-1150. The scope of the level-1 study includes plant damage state analysis, and uncertainty analysis. Volume 1 summarizes the results of the study. Internal events analysis is documented in Volume 2. It also contains an appendix that documents the part of the phase 1 study that has to do with POSs other than mid-loop operation. Internal fire and internal flood analyses are documented in Volumes 3 and 4. A separate study on seismic analysis, documented in Volume 5, was performed for the NRC by Future Resources Associates, Inc. Volume 6 documents the accident progression, source terms, and consequence analysis.

  15. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit-1: Analysis of core damage frequency from internal events during mid-loop operations. Appendices F-H, Volume 2, Part 4

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.; Yang, J.; Bozoki, G.; Hsu, C.J.; Diamond, D.J.; Bley, D.; Johnson, D.; Holmes, B.

    1994-06-01

    Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent studies and operational experience have implied that accidents during low power and shutdown could be significant contributors to risk. Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The scope of the program includes that of a level-3 PRA. In phase 2, mid-loop operation was selected as the plant configuration to be analyzed based on the results of the phase 1 study. The objective of the phase 2 study is to perform a detailed analysis of the potential accident scenarios that may occur during mid-loop operation, and compare the results with those of NUREG-1150. The scope of the level-1 study includes plant damage state analysis, and uncertainty analysis. Volume 1 summarizes the results of the study. Internal events analysis is documented in Volume 2. It also contains an appendix that documents the part of the phase 1 study that has to do with POSs other than mid-loop operation. Internal fire and internal flood analyses are documented in Volumes 3 and 4. A separate study on seismic analysis, documented in Volume 5, was performed for the NRC by Future Resources Associates, Inc. Volume 6 documents the accident progression, source terms, and consequence analysis

  16. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations. Appendix E (Sections E.9-E.16), Volume 2, Part 3B

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.; Yang, J.; Bozoki, G.; Hsu, C.J.; Diamond, D.J.; Wong, S.M.; Bley, D.; Johnson, D.

    1994-06-01

    Traditionally, probabilistic risk assessments (PRA) of severe accidents in nuclear power plants have considered initiating events potentially occurring only during full power operation. Some previous screening analyses that were performed for other modes of operation suggested that risks during those modes were small relative to full power operation. However, more recent studies and operational experience have implied that accidents during low power and shutdown could be significant contributors to risk. Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The scope of the program includes that of a level-3 PRA. In phase 2, mid-loop operation was selected as the plant configuration to be analyzed based on the results of the phase 1 study. The objective of the phase 2 study is to perform a detailed analysis of the potential accident scenarios that may occur during mid-loop operation, and compare the results with those of NUREG-1150. The scope of the level-1 study includes plant damage state analysis, and uncertainty analysis. Volume 1 summarizes the results of the study. Internal events analysis is documented in Volume 2. It also contains an appendix that documents the part of the phase 1 study that has to do with POSs other than mid-loop operation. Internal fire and internal flood analyses are documented in Volumes 3 and 4. A separate study on seismic analysis, documented in Volume 5, was performed for the NRC by Future Resources Associates, Inc. Volume 6 documents the accident progression, source terms, and consequence analysis

  17. Core damage frequency (reactor design) perspectives based on IPE results

    International Nuclear Information System (INIS)

    Camp, A.L.; Dingman, S.E.; Forester, J.A.

    1996-01-01

    This paper provides perspectives gained from reviewing 75 Individual Plant Examination (IPE) submittals covering 108 nuclear power plant units. Variability both within and among reactor types is examined to provide perspectives regarding plant-specific design and operational features, and C, modeling assumptions that play a significant role in the estimates of core damage frequencies in the IPEs. Human actions found to be important in boiling water reactors (BWRs) and in pressurized water reactors (PWRs) are presented and the events most frequently found important are discussed

  18. Analysis and research status of severe core damage accidents

    International Nuclear Information System (INIS)

    1984-03-01

    The Severe Core Damage Research and Analysis Task Force was established in Nuclear Safety Research Center, Tokai Research Establishment, JAERI, in May, 1982 to make a quantitative analysis on the issues related with the severe core damage accident and also to survey the present status of the research and provide the required research subjects on the severe core damage accident. This report summarizes the results of the works performed by the Task Force during last one and half years. The main subjects investigated are as follows; (1) Discussion on the purposes and necessities of severe core damage accident research, (2) proposal of phenomenological research subjects required in Japan, (3) analysis of severe core damage accidents and identification of risk dominant accident sequences, (4) investigation of significant physical phenomena in severe core damage accidents, and (5) survey of the research status. (author)

  19. Core damage frequency estimation using accident sequence precursor data: 1990-1993

    International Nuclear Information System (INIS)

    Martz, H.F.

    1998-01-01

    The Nuclear Regulatory Commission's (NRC's) ongoing Accident Sequence Precursor (ASP) program uses probabilistic risk assessment (PRA) techniques to assess the potential for severe core damage (henceforth referred to simply as core damage) based on operating events. The types of operating events considered include accident sequence initiators, safety equipment failures, and degradation of plant conditions that could increase the probability that various postulated accident sequences occur. Such operating events potentially reduce the margin of safety available for prevention of core damage an thus can be considered as precursors to core damage. The current process for identifying, analyzing, and documenting ASP events is described in detail in Vanden Heuval et al. The significance of a Licensee Event Report (LER) event (or events) is measured by means of the conditional probability that the event leads to core damage, the so-called conditional core damage probability or, simply, CCDP. When the first ASP study results were published in 1982, it covered the period 1969--1979. In addition to identification and ranking of precursors, the original study attempted to estimate core damage frequency (CDF) based on the precursor events. The purpose of this paper is to compare the average annual CDF estimates calculated using the CCDP sum, Cooke-Goossens, Bier, and Abramson estimators for various reactor classes using the combined ASP data for the four years, 1990--1993. An important outcome of this comparison is an answer to the persistent question regarding the degree and effect of the positive bias of the CCDP sum method in practice. Note that this paper only compares the estimators with each other. Because the true average CDF is unknown, the estimation error is also unknown. Therefore, any observations or characterizations of bias are based on purely theoretical considerations

  20. Alpha-decay event damage in zircon

    International Nuclear Information System (INIS)

    Murakami, Takashi; Chakoumakos, B.C.; Ewing, R.C.; Lumpkin, G.R.; Weber, W.J.

    1991-01-01

    Based on density measurements, X-ray diffraction analysis, and high-resolution transmission electron microscopy of a suite of natural zircon samples from Sri Lanka, three stages of damage accumulation may be delineated. Stage 1 ( 15 α-decay events/mg) is characterized by sharp Bragg diffraction maxima with a minor contribution from the diffuse-scattering component. Electron diffraction patterns were sharp. Damage is dominated by the accumulation of isolated point defects, which cause unit-cell expansion and distortion that account for most of the decrease in density. These defects may partially anneal over geologic periods of time. Stage 2 (3 x 10 15 to 8 x 10 15 α-decay events/mg) is characterized by significant decreases in the intensity of the Bragg diffraction maxima, which becomes asymmetric from increased contributions of the diffuse-scattering component. High-resolution transmission electron microscopy indicated that the microstructure consists of distorted crystalline regions and amorphous tracks caused by α-recoil nuclei. With increasing α-decay dose, damaged crystalline regions are converted into aperiodic regions but with no further significant expansion of the unit cell in the remaining crystalline regions. State 3 (> 8 x 10 15 α-decay events/mg) consists of material that is entirely aperiodic as far as can be determined by X-ray or electron diffraction. There was no evidence for the formation of ZrO 2 or SiO 2 as final products during the last stage of metamictization. Based on modeled density changes, aperiodic regions continue to experience a change in structure as they are redamaged

  1. Present status and needs of research on severe core damage

    International Nuclear Information System (INIS)

    1982-05-01

    The needs for research on severe core damage accident have been emphasized recently, in particular, since TMI-2 accident. The Severe Core Damage Research Task Force was established by the Divisions of Reactor Safety and Reactor Safety Evaluation to evaluate individual phenomenon, to survey the present status of research and to provide the recommended research subjects on severe accidents. This report describes the accident phenomena involving some analytical results, status of research and recommended research subjects on severe core damage accidents, divided into accident sequence, fuel damage, and molten material behavior, fission product behavior, hydrogen generation and combustion, steam explosion and containment integrity. (author)

  2. Evaluation of nuclear power plant component failure probability and core damage probability using simplified PSA model

    International Nuclear Information System (INIS)

    Shimada, Yoshio

    2000-01-01

    It is anticipated that the change of frequency of surveillance tests, preventive maintenance or parts replacement of safety related components may cause the change of component failure probability and result in the change of core damage probability. It is also anticipated that the change is different depending on the initiating event frequency or the component types. This study assessed the change of core damage probability using simplified PSA model capable of calculating core damage probability in a short time period, which is developed by the US NRC to process accident sequence precursors, when various component's failure probability is changed between 0 and 1, or Japanese or American initiating event frequency data are used. As a result of the analysis, (1) It was clarified that frequency of surveillance test, preventive maintenance or parts replacement of motor driven pumps (high pressure injection pumps, residual heat removal pumps, auxiliary feedwater pumps) should be carefully changed, since the core damage probability's change is large, when the base failure probability changes toward increasing direction. (2) Core damage probability change is insensitive to surveillance test frequency change, since the core damage probability change is small, when motor operated valves and turbine driven auxiliary feed water pump failure probability changes around one figure. (3) Core damage probability change is small, when Japanese failure probability data are applied to emergency diesel generator, even if failure probability changes one figure from the base value. On the other hand, when American failure probability data is applied, core damage probability increase is large, even if failure probability changes toward increasing direction. Therefore, when Japanese failure probability data is applied, core damage probability change is insensitive to surveillance tests frequency change etc. (author)

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

    International Nuclear Information System (INIS)

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

    1994-07-01

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

  4. TMI-2 core damage: a summary of present knowledge

    International Nuclear Information System (INIS)

    Owen, D.E.; Mason, R.E.; Meininger, R.D.; Franz, W.A.

    1983-01-01

    Extensive fuel damage (oxidation and fragmentation) has occurred and the top approx. 1.5 m of the center portion of the TMI-2 core has relocated. The fuel fragmentation extends outward to slightly beyond one-half the core radius in the direction examined by the CCTV camera. While the radial extent of core fragmentation in other directions was not directly observed, control and spider drop data and in-core instrument data suggest that the core void is roughly symmetrical, although there are a few indications of severe fuel damage extending to the core periphery. The core material fragmented into a broad range of particle sizes, extending down to a few microns. APSR movement data, the observation of damaged fuel assemblies hanging unsupported from the bottom of the reactor upper plenum structure, and the observation of once-molten stainless steel immediately above the active core indicate high temperatures (up to at least 1720 K) extended to the very top of the core. The relative lack of damage to the underside of the plenum structure implies a sharp temperature demarcation at the core/plenum interface. Filter debris and leadscrew deposit analyses indicate extensive high temperature core materials interaction, melting of the Ag-In-Cd control material, and transport of particulate control material to the plenum and out of the vessel

  5. Precursors to potential severe core damage accidents: 1992, A status report. Volume 17, Main report and Appendix A

    Energy Technology Data Exchange (ETDEWEB)

    Cox, D.F.; Cletcher, J.W.; Copinger, D.A.; Cross-Dial, A.E.; Morris, R.H.; Vanden Heuvel, L.N. [Oak Ridge National Lab., TN (United States); Dolan, B.W.; Jansen, J.M.; Minarick, J.W. [Science Applications International Corp., Oak Ridge, TN (United States); Lau, W.; Salyer, W.D. [Reliability and Performance Associates (United States)

    1993-12-01

    Twenty-seven operational events with conditional probabilities of subsequent severe core damage of 1.0 {times} 10E-06 or higher occurring at commercial light-water reactors during 1992 are considered to be precursors to potential core damage. These are described along with associated significance estimates, categorization, and subsequent analyses. The report discusses (1) the general rationale for this study, (2) the selection and documentation of events as precursors, (3) the estimation and use of conditional probabilities of subsequent severe core damage to rank precursor events, and (4) the plant models used in the analysis process.

  6. Precursors to potential severe core damage accidents: 1995 A status report

    International Nuclear Information System (INIS)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A.

    1997-04-01

    Ten operational events that affected 10 commercial light-water reactors during 1995 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10 -6 . These events were identified by first computer-screening the 1995 licensee event reports from commercial light-water reactors to identify those events that could potentially be precursors. Candidate precursors were selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969-1981 and 1984-1994 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events

  7. Precursors to potential severe core damage accidents: 1996. A status report. Volume 25

    International Nuclear Information System (INIS)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A.; Muhlheim, M.D.; Dolan, B.W.; Minarick, J.W.

    1997-12-01

    This report describes the 14 operational events in 1996 that affected 13 commercial light-water reactors and that are considered to be precursors to potential severe core damage accidents. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10 -6 . These events were identified by first computer-screening the 1996 licensee event reports from commercial light-water reactors to identify those events that could potentially be precursors. Candidate precursors were selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969--1995 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events

  8. Precursors to potential severe core damage accidents: 1995 A status report

    Energy Technology Data Exchange (ETDEWEB)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A. [and others

    1997-04-01

    Ten operational events that affected 10 commercial light-water reactors during 1995 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10{sup {minus}6}. These events were identified by first computer-screening the 1995 licensee event reports from commercial light-water reactors to identify those events that could potentially be precursors. Candidate precursors were selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969-1981 and 1984-1994 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events.

  9. Precursors to potential severe core damage accidents: 1997 - A status report. Volume 26

    International Nuclear Information System (INIS)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A.; Muhlheim, M.D.; Dolan, B.W.; Minarick, J.W.

    1998-11-01

    This report describes the five operational events in 1997 that affected five commercial light-water reactors (LWRs) and that are considered to be precursors to potential severe core damage accidents. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10 -6 . These events were identified by first computer-screening the 1997 licensee event reports from commercial LWRs to identify those events that could be precursors. Candidate precursors were selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters to ensure that the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969--1996 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for the events

  10. Containment loading during severe core damage accidents

    International Nuclear Information System (INIS)

    Fermandjian, J.; Evrard, J.M.; Cenerino, C.; Berthion, Y.; Carvallo, G.

    1984-11-01

    The objective of the article is to study the influence of the state of the reactor cavity (dry or flooded) and of the corium coolability on the thermal-hydraulics in the containment in the case of an accident sequence involving core melting and subsequent containment basemat erosion, in a 900 MWe PWR unit. Calculations are performed by using the JERICHO thermal hydraulics code

  11. Precursors to potential severe core damage accidents: 1994, a status report. Volume 22: Appendix I

    International Nuclear Information System (INIS)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A.; Vanden Heuvel, L.N.; Dolan, B.W.; Minarick, J.W.

    1995-12-01

    Nine operational events that affected eleven commercial light-water reactors (LWRs) during 1994 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10 -6 . These events were identified by computer-screening the 1994 licensee event reports from commercial LWRs to identify those that could be potential precursors. Candidate precursors were then selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure that the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969--1981 and 1984--1993 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for events. This document is bound in two volumes: Vol. 21 contains the main report and Appendices A--H; Vol. 22 contains Appendix 1

  12. Precursors to potential severe core damage accidents: 1994, a status report. Volume 22: Appendix I

    Energy Technology Data Exchange (ETDEWEB)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A.; Vanden Heuvel, L.N. [Oak Ridge National Lab., TN (United States); Dolan, B.W.; Minarick, J.W. [Oak Ridge National Lab., TN (United States)]|[Science Applications International Corp., Oak Ridge, TN (United States)

    1995-12-01

    Nine operational events that affected eleven commercial light-water reactors (LWRs) during 1994 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 {times} 10{sup {minus}6}. These events were identified by computer-screening the 1994 licensee event reports from commercial LWRs to identify those that could be potential precursors. Candidate precursors were then selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure that the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969--1981 and 1984--1993 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for events. This document is bound in two volumes: Vol. 21 contains the main report and Appendices A--H; Vol. 22 contains Appendix 1.

  13. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations, Appendices A--D. Volume 2, Part 2

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.

    1994-06-01

    During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the Potential risks during low Power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the Plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this report is to document the approach utilized in the Surry plant and discuss the results obtained. A parallel report for the Grand Gulf plant is prepared by SNL. This study shows that the core-damage frequency during mid-loop operation at the Surry plant is comparable to that of power operation. We recognize that there is very large uncertainty in the human error probabilities in this study. This study identified that only a few procedures are available for mitigating accidents that may occur during shutdown. Procedures written specifically for shutdown accidents would be useful. This document, Volume 2, Pt. 2 provides appendices A through D of this report

  14. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations, Main report (Chapters 7--12). Volume 2, Part 1B

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.

    1994-06-01

    During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this report is to document the approach utilized in the Surry plant and discuss the results obtained. A parallel report for the Grand Gulf plant is prepared by SNL. This study shows that the core-damage frequency during mid-loop operation at the Surry plant is comparable to that of power operation. We recognize that there is very large uncertainty in the human error probabilities in this study. This study identified that only a few procedures are available for mitigating accidents that may occur during shutdown. Procedures written specific shutdown accidents would be useful

  15. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations, Appendices E (Sections E.1--E.8). Volume 2, Part 3A

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.

    1994-06-01

    During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this report is to document the approach utilized in the Surry plant and discuss the results obtained. A parallel report for the Grand Gulf plant is prepared by SNL. This study shows that the core-damage frequency during mid-loop operation at the Surry plant is comparable to that of power operation. The authors recognize that there is very large uncertainty in the human error probabilities in this study. This study identified that only a few procedures are available for mitigating accidents that may occur during shutdown. Procedures written specifically for shutdown accidents would be useful

  16. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations, Main report (Chapters 1--6). Volume 2, Part 1A

    International Nuclear Information System (INIS)

    Chu, T.L.; Musicki, Z.; Kohut, P.

    1992-06-01

    During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this report is to document the approach utilized in the Surry plant and discuss the results obtained. A parallel report for the Grand Gulf plant is prepared by SNL. This study shows that the core-damage frequency during mid-loop operation at the Surry plant is comparable to that of power operation. We recognize that there is very large uncertainty in the human error probabilities in this study. This study identified that only a few procedures are available for mitigating accidents that may occur during shutdown written specifically for shutdown accidents would be useful. This document presents Chapters 1--6 of the report

  17. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal events during mid-loop operations, Appendices A--D. Volume 2, Part 2

    Energy Technology Data Exchange (ETDEWEB)

    Chu, T.L.; Musicki, Z.; Kohut, P. [Brookhaven National Lab., Upton, NY (United States)] [and others

    1994-06-01

    During 1989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the Potential risks during low Power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the Plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than full power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this report is to document the approach utilized in the Surry plant and discuss the results obtained. A parallel report for the Grand Gulf plant is prepared by SNL. This study shows that the core-damage frequency during mid-loop operation at the Surry plant is comparable to that of power operation. We recognize that there is very large uncertainty in the human error probabilities in this study. This study identified that only a few procedures are available for mitigating accidents that may occur during shutdown. Procedures written specifically for shutdown accidents would be useful. This document, Volume 2, Pt. 2 provides appendices A through D of this report.

  18. USNRC severe core damage assessment program

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, J E [EG and G Idaho, Inc., Idaho Falls (USA); Johnston, W V; Kelber, C N [Nuclear Regulatory Commission, Washington, DC (USA)

    1981-01-01

    The accident at the Three Mile Island nuclear power station has significantly altered the perception of the importance of beyond-design-basis accidents in licensing and safety reviews of light-water reactors in the USA. Increased consideration will be given by the United States Nuclear Regulatory Commission to low-probability, high-risk core melt accidents in future licensing proceedings. To this end, the USNRC is mounting experimental and analytic methods development programs to provide the technical basis for future LWR design and licensing criteria related to class-9 accidents. The scope, objectives, and content of five major new programs addressing safety and licensing issues for beyond-design-basis accidents are reviewed and the rationale and logic for formulation of the programs is discussed.

  19. Core rotational dynamics and geological events

    Science.gov (United States)

    Greff-Lefftz; Legros

    1999-11-26

    A study of Earth's fluid core oscillations induced by lunar-solar tidal forces, together with tidal secular deceleration of Earth's axial rotation, shows that the rotational eigenfrequency of the fluid core and some solar tidal waves were in resonance around 3.0 x 10(9), 1.8 x 10(9), and 3 x 10(8) years ago. The associated viscomagnetic frictional power at the core boundaries may be converted into heat and would destabilize the D" thermal layer, leading to the generation of deep-mantle plumes, and would also increase the temperature at the fluid core boundaries, perturbing the core dynamo process. Such phenomena could account for large-scale episodes of continental crust formation, the generation of flood basalts, and abrupt changes in geomagnetic reversal frequency.

  20. An estimation of core damage frequency of a pressurized water reactor during mid-loop operation

    International Nuclear Information System (INIS)

    Chao, C.C.; Chen, C.T.; Lee, M.

    2004-01-01

    The core damage frequency during mid-loop operation of a Westinghouse designed 3-loop Pressurizer Water Reactor (PWR) due to loss of Residual Heat Removal (RHR) events was assessed. The assessment considers two types of outages (refueling and drained maintenance), and uses failure data collected specifically for shutdown condition. Event trees were developed for five categories of loss of RHR events. Human actions to mitigate the loss of RHR events was identified and human error probabilities were quantified using HCR and THERP model. The result showed that the core damage frequency due to loss of RHR events during mid-loop operation is 3.1x10 -5 per year. The results also showed that the core damage frequency can be reduced significantly by removing a pressurizer safety valve before entering mid-loop operation. The establishment of reflux cooling, i.e. decay heat removal through steam generator secondary side also plays important role in mitigating the loss of RHR events. (author)

  1. Event course analysis of core disruptive accidents

    International Nuclear Information System (INIS)

    Hering, W.; Homann, C.; Sengpiel, W.; Struwe, D.; Messainguiral, C.

    1995-01-01

    The theortical studies of the behavior of a PWR core in a meltdown accident are focused on hydrogen release, materials redistribution in the core area including forming of an oxide melt pool, quantity of melt and its composition, and temperatures attained by the RPV internals (esp. in the upper plenum) during the accident up to the time of melt relocation into the lower plenum. The calculations are done by the SCDAP/RELAP5 code. For its validation selected CORA results and Phebus FPTO results have been used. (orig.)

  2. Vegetation damage and recovery after Chiginagak Volcano Crater drainage event

    Data.gov (United States)

    Department of the Interior — From August 20 — 23, 2006, I revisited Chiginigak volcano to document vegetation recovery after the crater drainage event that severely damaged vegetation in May of...

  3. Severe core damage experiments and analysis for CANDU applications

    International Nuclear Information System (INIS)

    Mathew, P.M.; White, A.J.; Snell, V.G.; Bonechi, M.

    2003-01-01

    AECL uses the MAAP CANDU code to calculate the progression of a severe core damage accident in a CANDU reactor to support Level 2 Probabilistic Safety Assessment and Severe Accident Management activities. Experimental data are required to ensure that the core damage models used in MAAP CANDU code are adequate. In SMiRT 16, details of single channel experiments were presented to elucidate the mechanisms of core debris formation. This paper presents the progress made in severe core damage experiments since then using single channels in an inert atmosphere and results of the model development work to support the experiments. The core disassembly experiments are conducted with one-fifth scale channels made of Zr-2.5wt%Nb containing twelve simulated fuel bundles in an inert atmosphere. The reference fuel channel geometry consists of a pressure tube/calandria tube composite, with the pressure tube ballooned into circumferential contact with the calandria tube. Experimental results from single channel tests showed the development of time-dependent sag when the reference channel temperature exceeded 850 degC. The test results also showed significant strain localization in the gap at the bundle junctions along the bottom side of the channel, thus suggesting creep to be the main deformation mechanism for debris formation. An ABAQUS finite element model using two-dimensional beam elements with circular cross-section was developed to explain the experimental findings. A comparison of the calculated central sag (at mid-span), the axial displacement at the free end of the channel and the post-test sag profile showed good agreement with the experiments, when strain localization was included in the model, suggesting such a simple modelling approach would be adequate to explain the test findings. The results of the tests are important not only in the context of the validation of the analytical tools and models adopted by AECL for the severe accident analysis of CANDU reactors but

  4. Analysis of severe core damage accident progression for the heavy water reactor

    International Nuclear Information System (INIS)

    Tong Lili; Yuan Kai; Yuan Jingtian; Cao Xuewu

    2010-01-01

    In this study, the severe accident progression analysis of generic Canadian deuterium uranium reactor 6 was preliminarily provided using an integrated severe accident analysis code. The selected accident sequences were multiple steam generator tube rupture and large break loss-of-coolant accidents because these led to severe core damage with an assumed unavailability for several critical safety systems. The progressions of severe accident included a set of failed safety systems normally operated at full power, and initiative events led to primary heat transport system inventory blow-down or boil off. The core heat-up and melting, steam generator response,fuel channel and calandria vessel failure were analyzed. The results showed that the progression of a severe core damage accident induced by steam generator tube rupture or large break loss-of-coolant accidents in a CANDU reactor was slow due to heat sinks in the calandria vessel and vault. (authors)

  5. Quantification of LOCA core damage frequency based on thermal-hydraulics analysis

    International Nuclear Information System (INIS)

    Cho, Jaehyun; Park, Jin Hee; Kim, Dong-San; Lim, Ho-Gon

    2017-01-01

    Highlights: • We quantified the LOCA core damage frequency based on the best-estimated success criteria analysis. • The thermal-hydraulic analysis using MARS code has been applied to Korea Standard Nuclear Power Plants. • Five new event trees with new break size boundaries and new success criteria were developed. • The core damage frequency is 5.80E−07 (/y), which is 12% less than the conventional PSA event trees. - Abstract: A loss-of-coolant accident (LOCA) has always been significantly considered one of the most important initiating events. However, most probabilistic safety assessment models, up to now, have undoubtedly adopted the three groups of LOCA, and even an exact break size boundary that used in WASH-1400 reports was published in 1975. With an awareness of the importance of a realistic PSA for a risk-informed application, several studies have tried to find the realistic thermal-hydraulic behavior of a LOCA, and improve the PSA model. The purpose of this research is to obtain realistic results of the LOCA core damage frequency based on a success criteria analysis using the best-estimate thermal-hydraulics code. To do so, the Korea Standard Nuclear Power Plant (KSNP) was selected for this study. The MARS code was used for a thermal hydraulics analysis and the AIMS code was used for the core damage quantification. One of the major findings in the thermal hydraulics analysis was that the decay power is well removed by only a normal secondary cooling in LOCAs of below 1.4 in and by only a high pressure safety injection in LOCAs of 0.8–9.4 in. Based on the thermal hydraulics results regarding new break size boundaries and new success criteria, five new event trees (ETs) were developed. The core damage frequency of new LOCA ETs is 5.80E−07 (/y), which is 12% less than the conventional PSA ETs. In this research, we obtained not only thermal-hydraulics characteristics for the entire break size of a LOCA in view of the deterministic safety

  6. Quantification of LOCA core damage frequency based on thermal-hydraulics analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Jaehyun, E-mail: chojh@kaeri.re.kr; Park, Jin Hee; Kim, Dong-San; Lim, Ho-Gon

    2017-04-15

    Highlights: • We quantified the LOCA core damage frequency based on the best-estimated success criteria analysis. • The thermal-hydraulic analysis using MARS code has been applied to Korea Standard Nuclear Power Plants. • Five new event trees with new break size boundaries and new success criteria were developed. • The core damage frequency is 5.80E−07 (/y), which is 12% less than the conventional PSA event trees. - Abstract: A loss-of-coolant accident (LOCA) has always been significantly considered one of the most important initiating events. However, most probabilistic safety assessment models, up to now, have undoubtedly adopted the three groups of LOCA, and even an exact break size boundary that used in WASH-1400 reports was published in 1975. With an awareness of the importance of a realistic PSA for a risk-informed application, several studies have tried to find the realistic thermal-hydraulic behavior of a LOCA, and improve the PSA model. The purpose of this research is to obtain realistic results of the LOCA core damage frequency based on a success criteria analysis using the best-estimate thermal-hydraulics code. To do so, the Korea Standard Nuclear Power Plant (KSNP) was selected for this study. The MARS code was used for a thermal hydraulics analysis and the AIMS code was used for the core damage quantification. One of the major findings in the thermal hydraulics analysis was that the decay power is well removed by only a normal secondary cooling in LOCAs of below 1.4 in and by only a high pressure safety injection in LOCAs of 0.8–9.4 in. Based on the thermal hydraulics results regarding new break size boundaries and new success criteria, five new event trees (ETs) were developed. The core damage frequency of new LOCA ETs is 5.80E−07 (/y), which is 12% less than the conventional PSA ETs. In this research, we obtained not only thermal-hydraulics characteristics for the entire break size of a LOCA in view of the deterministic safety

  7. Modeling of reflood of severely damaged reactor core

    International Nuclear Information System (INIS)

    Bachrata, A.

    2012-01-01

    The TMI-2 accident and recently Fukushima accident demonstrated that the nuclear safety philosophy has to cover accident sequences involving massive core melt in order to develop reliable mitigation strategies for both, existing and advanced reactors. Although severe accidents are low likelihood and might be caused only by multiple failures, accident management is implemented for controlling their course and mitigating their consequences. In case of severe accident, the fuel rods may be severely damaged and oxidized. Finally, they collapse and form a debris bed on core support plate. Removal of decay heat from a damaged core is a challenging issue because of the difficulty for water to penetrate inside a porous medium. The reflooding (injection of water into core) may be applied only if the availability of safety injection is recovered during accident. If the injection becomes available only in the late phase of accident, water will enter a core configuration that will differ from original rod bundle geometry and will resemble to the severe damaged core observed in TMI-2. The higher temperatures and smaller hydraulic diameters in a porous medium make the coolability more difficult than for intact fuel rods under typical loss of coolant accident conditions. The modeling of this kind of hydraulic and heat transfer is a one of key objectives of this. At IRSN, part of the studies is realized using an European thermo-hydraulic computer code for severe accident analysis ICARE-CATHARE. The objective of this thesis is to develop a 3D reflood model (implemented into ICARE-CATHARE) that is able to treat different configurations of degraded core in a case of severe accident. The proposed model is characterized by treating of non-equilibrium thermal between the solid, liquid and gas phase. It includes also two momentum balance equations. The model is based on a previously developed model but is improved in order to take into account intense boiling regimes (in particular

  8. The ATLAS Event Index: The Architecture of the Core Engine

    CERN Document Server

    Barberis, Dario; The ATLAS collaboration

    2017-01-01

    The global view of the ATLAS Event Index system has been presented in the 17th ACAT Conference. This article concentrates on the architecture of the system core component. This component handles the final stage of the event metadata import, it organizes its storage and provides a fast and feature-rich access to all information. A user is able to interrogate metadata in various ways, including by executing user-provided code on the data to make selections and to interpret the results. A wide spectrum of clients is available, from a set of linux-like commands to an interactive graphical Web Service. The stored event metadata contain the basic description of the related events, the references to the experiment event storage, the full trigger record and can be extended with other event characteristics. Derived collections of events can be created. Such collections can be annotated and tagged with further information.

  9. Core damage frequency perspectives based on IPE results

    International Nuclear Information System (INIS)

    Dingman, S.E.; Camp, A.L.; LaChance, J.L.; Drouin, M.T.

    1996-01-01

    In November 1988, the US Nuclear Regulatory Commission (NRC) issued Generic Letter 88-20 requesting that all licensees perform an individual Plant Examination (IPE) to identify any plant-specific vulnerability to severe accidents and report the results to the Commission. This paper provides perspectives gained from reviewing 75 Individual Plant Examination (IPE) submittals covering 108 nuclear power plant units. Variability both within and among reactor types is examined to provide perspectives regarding plant-specific design and operational features, and modeling assumptions that play a significant role in the estimates of core damage frequencies in the IPEs

  10. Assessment of core damage frequency owing to possible fires at NPP with RBMK type reactors

    Energy Technology Data Exchange (ETDEWEB)

    Vinnikov, B. [National Research Centre Kurchatov Inst., 1, Kurchatov Square, Moscow, 123 182 (Russian Federation); NRC Kurchatov Inst. (Russian Federation)

    2012-07-01

    According to Scientific and Technical Cooperation between the USA and Russia in the field of nuclear engineering the Idaho National Laboratory has transferred to the possession of the National Research Center ' Kurchatov Inst. ' the SAPHIRE software without any fee. With the help of the software Kurchatov Inst. developed a Pilot Living PSA- Model of Leningrad NPP Unit 1. Computations of core damage frequencies were carried out for additional Initiating Events. In the submitted paper such additional Initiating Events are fires in various compartments of the NPP. During the computations of each fire, structure of the PSA - Model was not changed, but Fault Trees for the appropriate systems, which are removed from service during the fire, were changed. It follows from the computations, that for ten fires Core Damaged Frequencies (CDF) are not changed. Other six fires will cause additional core damage. On the basis of the calculated results it is possible to determine a degree of importance of these fires and to establish sequence of performance of fire-prevention measures in various places of the NPP. (authors)

  11. Assessment of core damage frequency owing to possible fires at NPP with RBMK type reactors

    International Nuclear Information System (INIS)

    Vinnikov, B.

    2012-01-01

    According to Scientific and Technical Cooperation between the USA and Russia in the field of nuclear engineering the Idaho National Laboratory has transferred to the possession of the National Research Center ' Kurchatov Inst. ' the SAPHIRE software without any fee. With the help of the software Kurchatov Inst. developed a Pilot Living PSA- Model of Leningrad NPP Unit 1. Computations of core damage frequencies were carried out for additional Initiating Events. In the submitted paper such additional Initiating Events are fires in various compartments of the NPP. During the computations of each fire, structure of the PSA - Model was not changed, but Fault Trees for the appropriate systems, which are removed from service during the fire, were changed. It follows from the computations, that for ten fires Core Damaged Frequencies (CDF) are not changed. Other six fires will cause additional core damage. On the basis of the calculated results it is possible to determine a degree of importance of these fires and to establish sequence of performance of fire-prevention measures in various places of the NPP. (authors)

  12. Precursors to potential severe core damage accidents: 1994, a status report. Volume 21: Main report and appendices A--H

    International Nuclear Information System (INIS)

    Belles, R.J.; Cletcher, J.W.; Copinger, D.A.; Vanden Heuvel, L.N.; Dolan, B.W.; Minarick, J.W.

    1995-12-01

    Nine operational events that affected eleven commercial light-water reactors (LWRs) during 1994 and that are considered to be precursors to potential severe core damage are described. All these events had conditional probabilities of subsequent severe core damage greater than or equal to 1.0 x 10 -6 . These events were identified by computer-screening the 1994 licensee event reports from commercial LWRs to identify those that could be potential precursors. Candidate precursors were then selected and evaluated in a process similar to that used in previous assessments. Selected events underwent engineering evaluation that identified, analyzed, and documented the precursors. Other events designated by the Nuclear Regulatory Commission (NRC) also underwent a similar evaluation. Finally, documented precursors were submitted for review by licensees and NRC headquarters and regional offices to ensure that the plant design and its response to the precursor were correctly characterized. This study is a continuation of earlier work, which evaluated 1969--1981 and 1984--1993 events. The report discusses the general rationale for this study, the selection and documentation of events as precursors, and the estimation of conditional probabilities of subsequent severe core damage for events. This document is bound in two volumes: Vol. 21 contains the main report and Appendices A--H; Vol. 22 contains Appendix 1

  13. Climate Change : Behavioral Responses from Extreme Events and Delayed Damages

    NARCIS (Netherlands)

    Ghidoni, Riccardo; Calzolari, G.; Casari, Marco

    2017-01-01

    Understanding how to sustain cooperation in the climate change global dilemma is crucial to mitigate its harmful consequences. Damages from climate change typically occurs after long delays and can take the form of more frequent realizations of extreme and random events. These features generate a

  14. Climate change : Behavioral responses from extreme events and delayed damages

    NARCIS (Netherlands)

    Ghidoni, Riccardo; Calzolari, Giacomo; Casari, Marco

    2017-01-01

    Understanding how to sustain cooperation in the climate change global dilemma is crucial to mitigate its harmful consequences. Damages from climate change typically occur after long delays and can take the form of more frequent realizations of extreme and random events. These features generate a

  15. The study of past damaging hydrogeological events for damage susceptibility zonation

    Directory of Open Access Journals (Sweden)

    O. Petrucci

    2008-08-01

    Full Text Available Damaging Hydrogeological Events are defined as periods during which phenomena, such as landslides, floods and secondary floods, cause damage to people and the environment.

    A Damaging Hydrogeological Event which heavily damaged Calabria (Southern Italy between December 1972, and January 1973, has been used to test a procedure to be utilised in the zonation of a province according to damage susceptibility during DHEs. In particular, we analyzed the province of Catanzaro (2391 km2, an administrative district composed of 80 municipalities, with about 370 000 inhabitants.

    Damage, defined in relation to the reimbursement requests sent to the Department of Public Works, has been quantified using a procedure based on a Local Damage Index. The latter, representing classified losses, has been obtained by multiplying the value of the damaged element and the percentage of damage affecting it.

    Rainfall has been described by the Maximum Return Period of cumulative rainfall, for both short (1, 3, 5, 7, 10 consecutive days and long duration (30, 60, 90, 180 consecutive days, recorded during the event.

    Damage index and population density, presumed to represent the location of vulnerable elements, have been referred to Thiessen polygons associated to rain gauges working at the time of the event.

    The procedure allowed us to carry out a preliminary classification of the polygons composing the province according to their susceptibility to damage during DHEs. In high susceptibility polygons, severe damage occurs during rainfall characterised by low return periods; in medium susceptibility polygons maximum return period rainfall and induced damage show equal levels of exceptionality; in low susceptibility polygons, high return period rainfall induces a low level of damage.

    The east and west sectors of the province show the highest susceptibility, while polygons of the N-NE sector show the lowest

  16. An examination of impact damage in glass-phenolic and aluminum honeycomb core composite panels

    Science.gov (United States)

    Nettles, A. T.; Lance, D. G.; Hodge, A. J.

    1990-01-01

    An examination of low velocity impact damage to glass-phenolic and aluminum core honeycomb sandwich panels with carbon-epoxy facesheets is presented. An instrumented drop weight impact test apparatus was utilized to inflict damage at energy ranges between 0.7 and 4.2 joules. Specimens were checked for extent of damage by cross sectional examination. The effect of core damage was assessed by subjecting impact-damaged beams to four-point bend tests. Skin-only specimens (facings not bonded to honeycomb) were also tested for comparison purposes. Results show that core buckling is the first damage mode, followed by delaminations in the facings, matrix cracking, and finally fiber breakage. The aluminum honeycomb panels exhibited a larger core damage zone and more facing delaminations than the glass-phenolic core, but could withstand more shear stress when damaged than the glass-phenolic core specimens.

  17. Estimation of Damage Costs Associated with Flood Events

    Science.gov (United States)

    Andrews, T. A.; Wauthier, C.; Zipp, K.

    2017-12-01

    This study investigates the possibility of creating a mathematical function that enables the estimation of flood-damage costs. We begin by examining the costs associated with past flood events in the United States. The data on these tropical storms and hurricanes are provided by the National Oceanic and Atmospheric Administration. With the location, extent of flooding, and damage reparation costs identified, we analyze variables such as: number of inches rained, land elevation, type of landscape, region development in regards to building density and infrastructure, and population concentration. We seek to identify the leading drivers of high flood-damage costs and understand which variables play a large role in the costliness of these weather events. Upon completion of our mathematical analysis, we turn out attention to the 2017 natural disaster of Texas. We divide the region, as we did above, by land elevation, type of landscape, region development in regards to building density and infrastructure, and population concentration. Then, we overlay the number of inches rained in those regions onto the divided landscape and apply our function. We hope to use these findings to estimate the potential flood-damage costs of Hurricane Harvey. This information is then transformed into a hazard map that could provide citizens and businesses of flood-stricken zones additional resources for their insurance selection process.

  18. Tracking the El Nino events from Antarctic ice core records

    International Nuclear Information System (INIS)

    Keskin, S.S.; Oelmez, I.

    2004-01-01

    Sodium and chlorine measurements were made by instrumental neutron activation analysis (INAA) on stratigraphically dated ice core samples from Byrd Station, Antarctica, for the last three centuries. The time period between 1969 and 1989 showed an enhanced impact on the Antarctic ice sheets from oceans in the form of marine aerosols. A disturbed ocean-atmosphere interface due to El Ni Southern Oscillation (ENSO) events seems to be a candidate for this observation in Antarctica. (author)

  19. The effect of uncertainties in nuclear reactor plant-specific failure data on core damage frequency

    International Nuclear Information System (INIS)

    Martz, H.F.

    1995-05-01

    It is sometimes the case in PRA applications that reported plant-specific failure data are, in fact, only estimates which are uncertain. Even for detailed plant-specific data, the reported exposure time or number of demands is often only an estimate of the actual exposure time or number of demands. Likewise the reported number of failure events or incidents is sometimes also uncertain because incident or malfunction reports may be ambiguous. In this report we determine the corresponding uncertainty in core damage frequency which can b attributed to such uncertainties in plant-specific data using a simple but typical nuclear power reactor example

  20. The ATLAS Event Index: The Architecture of the Core Engine

    CERN Document Server

    Barberis, Dario; The ATLAS collaboration; Hrivnac, Julius

    2017-01-01

    The global view of the ATLAS Event Index system has been presented in the last ACAT. This talk will concentrate on the architecture of the system core component. This component handles the final stage of the event metadata import, it organizes its storage and provides a fast and feature-rich access to all information. A user is able to interrogate metadata in various ways, including by executing user-provided code on the data to make selections and to interpret the results. A wide spectrum of clients is available, from a set of linux-like commands to an interactive graphical Web Service. The stored event metadata contain the basic description of the related events, the references to the experiment event storage, the full trigger record and can be extended with other event characteristics. Derived collections of events can be created. Such collections can be annotated and tagged with further information. This talk will describe all system sub-components and their development evolution, which lead into the choi...

  1. Parameters affecting of Akkuyu's safety assessment for severe core damages

    Science.gov (United States)

    Kavun, Yusuf; Karasulu, Muzaffer

    2015-07-01

    We have looked at all past core meltdowns (Three Mile Island, Chernobyl and Fukushima incidents) and postulated the fourth one might be taking place in the future most probably in a newly built reactors anywhere of the earth in any type of NPP. The probability of this observation is high considering the nature of the machine and human interaction. Operation experience is a very significant parameter as well as the safety culture of the host nation. The concerns is not just a lack of experience with industry with the new comers, but also the infrastructure and established institutions who will be dealing with the Emergencies. Lack of trained and educated Emergency Response Organizations (ERO) is a major concern. The culture on simple fire drills even makes the difference when a severe condition occurs in the industry. The study assumes the fourth event will be taking place at the Akkuyu NGS and works backwards as required by the "what went wrong " scenarios and comes up with interesting results. The differences studied in depth to determine the impact to the severe accidents. The all four design have now core catchers. We have looked at the operator errors'like in TMI); Operator errors combined with design deficiencies(like in Chernobyl) and natural disasters( like in Fukushima) and found operator errors to be more probable event on the Akkuyu's postulated next incident. With respect to experiences of the operators we do not have any data except for long and successful operating history of the Soviet design reactors up until the Chernobyl incident. Since the Akkuyu will be built, own and operated by the Russians we have found no alarming concerns at the moment. At the moment, there is no body be able to operate those units in Turkey. Turkey is planning to build the required manpower during the transition period. The resolution of the observed parameters lies to work and educate, train of the host nation and exercise together.

  2. Predictions for microlensing planetary events from core accretion theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wei; Mao, Shude [National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China); Penny, Matthew; Gould, Andrew [Department of Astronomy, The Ohio State University, 140 W. 18th Avenue, Columbus, OH 43210 (United States); Gendron, Rieul, E-mail: weizhu@astronomy.ohio-state.edu [Jodrell Bank Centre for Astrophysics, University of Manchester, Alan Turing Building, Manchester M13 9PL (United Kingdom)

    2014-06-10

    We conduct the first microlensing simulation in the context of a planet formation model. The planet population is taken from the Ida and Lin core accretion model for 0.3 M {sub ☉} stars. With 6690 microlensing events, we find that for a simplified Korea Microlensing Telescopes Network (KMTNet), the fraction of planetary events is 2.9%, out of which 5.5% show multiple-planet signatures. The numbers of super-Earths, super-Neptunes, and super-Jupiters detected are expected to be almost equal. Our simulation shows that high-magnification events and massive planets are favored by planet detections, which is consistent with previous expectation. However, we notice that extremely high-magnification events are less sensitive to planets, which is possibly because the 10 minute sampling of KMTNet is not intensive enough to capture the subtle anomalies that occur near the peak. This suggests that while KMTNet observations can be systematically analyzed without reference to any follow-up data, follow-up observations will be essential in extracting the full science potential of very high magnification events. The uniformly high-cadence observations expected for KMTNet also result in ∼55% of all detected planets not being caustic crossing, and more low-mass planets even down to Mars mass being detected via planetary caustics. We also find that the distributions of orbital inclinations and planet mass ratios in multiple-planet events agree with the intrinsic distributions.

  3. Predictions for microlensing planetary events from core accretion theory

    International Nuclear Information System (INIS)

    Zhu, Wei; Mao, Shude; Penny, Matthew; Gould, Andrew; Gendron, Rieul

    2014-01-01

    We conduct the first microlensing simulation in the context of a planet formation model. The planet population is taken from the Ida and Lin core accretion model for 0.3 M ☉ stars. With 6690 microlensing events, we find that for a simplified Korea Microlensing Telescopes Network (KMTNet), the fraction of planetary events is 2.9%, out of which 5.5% show multiple-planet signatures. The numbers of super-Earths, super-Neptunes, and super-Jupiters detected are expected to be almost equal. Our simulation shows that high-magnification events and massive planets are favored by planet detections, which is consistent with previous expectation. However, we notice that extremely high-magnification events are less sensitive to planets, which is possibly because the 10 minute sampling of KMTNet is not intensive enough to capture the subtle anomalies that occur near the peak. This suggests that while KMTNet observations can be systematically analyzed without reference to any follow-up data, follow-up observations will be essential in extracting the full science potential of very high magnification events. The uniformly high-cadence observations expected for KMTNet also result in ∼55% of all detected planets not being caustic crossing, and more low-mass planets even down to Mars mass being detected via planetary caustics. We also find that the distributions of orbital inclinations and planet mass ratios in multiple-planet events agree with the intrinsic distributions.

  4. Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    A face/core debond in a sandwich structure may propagate in the interface or kink into either the face or core. It is found that certain modifications of the face/core interface region influence the kinking behavior, which is studied experimentally in the present paper. A sandwich double cantilever....... The transition points where the crack kinks are identified and the influence of four various interface design modifications on the propagation path and fracture resistance are investigated....

  5. Identifying Preserved Storm Events on Beaches from Trenches and Cores

    Science.gov (United States)

    Wadman, H. M.; Gallagher, E. L.; McNinch, J.; Reniers, A.; Koktas, M.

    2014-12-01

    Recent research suggests that even small scale variations in grain size in the shallow stratigraphy of sandy beaches can significantly influence large-scale morphology change. However, few quantitative studies of variations in shallow stratigraphic layers, as differentiated by variations in mean grain size, have been conducted, in no small part due to the difficulty of collecting undisturbed sediment cores in the energetic lower beach and swash zone. Due to this lack of quantitative stratigraphic grain size data, most coastal morphology models assume that uniform grain sizes dominate sandy beaches, allowing for little to no temporal or spatial variations in grain size heterogeneity. In a first-order attempt to quantify small-scale, temporal and spatial variations in beach stratigraphy, thirty-five vibracores were collected at the USACE Field Research Facility (FRF), Duck, NC, in March-April of 2014 using the FRF's Coastal Research and Amphibious Buggy (CRAB). Vibracores were collected at set locations along a cross-shore profile from the toe of the dune to a water depth of ~1m in the surf zone. Vibracores were repeatedly collected from the same locations throughout a tidal cycle, as well as pre- and post a nor'easter event. In addition, two ~1.5m deep trenches were dug in the cross-shore and along-shore directions (each ~14m in length) after coring was completed to allow better interpretation of the stratigraphic sequences observed in the vibracores. The elevations of coherent stratigraphic layers, as revealed in vibracore-based fence diagrams and trench data, are used to relate specific observed stratigraphic sequences to individual storm events observed at the FRF. These data provide a first-order, quantitative examination of the small-scale temporal and spatial variability of shallow grain size along an open, sandy coastline. The data will be used to refine morphological model predictions to include variations in grain size and associated shallow stratigraphy.

  6. Indemnification of damage in the event of a nuclear accident

    International Nuclear Information System (INIS)

    2003-01-01

    The Workshop on the Indemnification of Damage in the Event of a Nuclear Accident, organised by the OECD Nuclear Energy Agency in close co-operation with the French authorities, was held in Paris from 26 to 28 November 2001. This event was an integral part of the International Nuclear Emergency Exercise INEX 2000. It attracted wide participation from national nuclear authorities, regulators, operators of nuclear installations, nuclear insurers and international organisations. The objective was to test the capacity of the existing nuclear liability and compensation mechanisms in the 29 countries represented at the workshop to manage the consequences of a nuclear emergency. This workshop was based upon the scenario used for the INEX 2000 Exercise, i.e. an accident simulated at the Gravelines nuclear power plant in the north of France in May 2001. These proceedings contain a comparative analysis of legislative and regulatory provisions governing emergency response and nuclear third party liability, based upon country replies to a questionnaire. This publication also includes the full responses provided to that questionnaire, as well as the texts of presentations made by special guests from Germany and Japan describing the manner in which the public authorities in their respective countries responded to two nuclear accidents of a very different nature and scale. (authors)

  7. Indemnification of Damage in the Event of a Nuclear Accident

    International Nuclear Information System (INIS)

    2006-01-01

    The Second International Workshop on the Indemnification of Nuclear Damage was held in Bratislava, Slovak Republic, from 18 to 20 May 2005. The workshop was co-organised by the OECD Nuclear Energy Agency and the Nuclear Regulatory Authority of the Slovak Republic. It attracted wide participation from national nuclear authorities, regulators, operators of nuclear installations, nuclear insurers and international organisations. The purpose of the workshop was to assess the third party liability and compensation mechanisms that would be implemented by participating countries in the event of a nuclear accident taking place within or near their borders. To accommodate this objective, two fictitious accident scenarios were developed: one involving a fire in a nuclear installation located in the Slovak Republic and resulting in the release of significant amounts of radioactive materials off-site, and the other a fire on board a ship transporting enriched uranium hexafluoride along the Danube River. The first scenario was designed to involve the greatest possible number of countries, with the second being restricted to countries with a geographical proximity to the Danube. These proceedings contain the papers presented at the workshop, as well as reports on the discussion sessions held. (author)

  8. Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

    2010-01-01

    Various modifications of the face/core interface in foam core sandwich specimens are examined in a series of two papers. This paper constitutes part I and describes the finite element analysis of a sandwich test specimen, i.e. a DCB specimen loaded by uneven bending moments (DCB-UBM). Using...... this test almost any mode-mixity between pure mode I and mode II can be obtained. A cohesive zone model of the mixed mode fracture process involving large-scale bridging is developed. Results from the analysis are used in Part II, which describes methods and results of a series of experiments....

  9. Stiffness and strength degradation of damaged truss core composites

    Czech Academy of Sciences Publication Activity Database

    Šiška, Filip; Tawfeeq, Arwa F.; Dlouhý, I.; Barnett, M.R.

    2015-01-01

    Roč. 125, JUL (2015), s. 287-294 ISSN 0263-8223 R&D Projects: GA MŠk EE2.3.20.0197 Institutional support: RVO:68081723 Keywords : Truss core composites * Finite element * Strain rate * High temperature tests Subject RIV: JI - Composite Materials Impact factor: 3.853, year: 2015

  10. Phenomena occurring in the reactor coolant system during severe core damage accidents

    International Nuclear Information System (INIS)

    Malinauskas, A.P.

    1989-01-01

    The reactor coolant system (RCS) of a nuclear power plant consists of the reactor pressure vessel and the piping and associated components that are required for the continuous circulation of the coolant which is used to maintain thermal equilibrium throughout the system. In the event of an accident, the RCS also serves as one of several barriers to the escape of radiotoxic material into the biosphere. In contrast to normal operating conditions, severe core damage accidents are characterized by significant temporal and spatial variations in heat and mass fluxes, and by eventual geometrical changes within the RCS. Furthermore, the difficulties in describing the system in the severe accident mode are compounded by the occurrence of chemical reactions. These reactions can influence both the thermal and the mass transport behavior of the system. In addition, behavior of the reactor vessel internals and of materials released from the core region (especially the radioactive fission products) in the course of the accident likewise become of concern to the analyst. This report addresses these concerns. 9 refs., 1 tab

  11. Management of radioactive waste from a major core damage in a BWR power plant

    International Nuclear Information System (INIS)

    Elkert, J.; Christensen, H.; Torstenfelt, B.

    1990-01-01

    Large amounts of fission products would be released in case of a major core damage in a nuclear power reactor. In this theoretical study the core damage is caused by a loss of coolant accident followed by a complete loss of all electric power for about 30 minutes resulting in the release of 10% of the core inventory of noble gases. A second case has also been briefly studied, in which the corresponding core damage is supposed to be created merely by the complete loss of electric power during a limited time period. It appears from the study that the radioactive waste generated as a consequence of an accident of the extent can be managed in the reference reactor with only minor modifications required in the waste plant. The detailed results of the study are reactor specific, but many of the findings and recommendations are generally applicable. (author) 28 refs

  12. Calculation of the Incremental Conditional Core Damage Probability on the Extension of Allowed Outage Time

    International Nuclear Information System (INIS)

    Kang, Dae Il; Han, Sang Hoon

    2006-01-01

    RG 1.177 requires that the conditional risk (incremental conditional core damage probability and incremental conditional large early release probability: ICCDP and ICLERP), given that a specific component is out of service (OOS), be quantified for a permanent change of the allowed outage time (AOT) of a safety system. An AOT is the length of time that a particular component or system is permitted to be OOS while the plant is operating. The ICCDP is defined as: ICCDP = [(conditional CDF with the subject equipment OOS)- (baseline CDF with nominal expected equipment unavailabilities)] [duration of the single AOT under consideration]. Any event enabling the component OOS can initiate the time clock for the limiting condition of operation for a nuclear power plant. Thus, the largest ICCDP among the ICCDPs estimated from any occurrence of the basic events for the component fault tree should be selected for determining whether the AOT can be extended or not. If the component is under a preventive maintenance, the conditional risk can be straightforwardly calculated without changing the CCF probability. The main concern is the estimations of the CCF probability because there are the possibilities of the failures of other similar components due to the same root causes. The quantifications of the risk, given that a subject equipment is in a failed state, are performed by setting the identified event of subject equipment to TRUE. The CCF probabilities are also changed according to the identified failure cause. In the previous studies, however, the ICCDP was quantified with the consideration of the possibility of a simultaneous occurrence of two CCF events. Based on the above, we derived the formulas of the CCF probabilities for the cases where a specific component is in a failed state and we presented sample calculation results of the ICCDP for the low pressure safety injection system (LPSIS) of Ulchin Unit 3

  13. Modeling and analysis framework for core damage propagation during flow-blockage-initiated accidents in the advanced neutron source reactor at Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V. [Oak Ridge National Lab., TN (United States)

    1995-09-01

    This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at the Oak Ridge National Laboratory (ORNL). Damage propagation is postulated to occur from thermal conduction between damaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur because of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A scoping study was conducted to learn what parameters are important for core damage propagation, and to obtain initial estimates of core melt mass for addressing recriticality and steam explosion events. The study included investigating the effect of the plate contact area, the convective heat transfer coefficient, thermal conductivity upon fuel swelling, and the initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects on damage propagation. The results provide useful insights into how various uncertain parameters affect damage propagation.

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

    International Nuclear Information System (INIS)

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

    1994-06-01

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

  15. SCDAP: a light water reactor computer code for severe core damage analysis

    International Nuclear Information System (INIS)

    Marino, G.P.; Allison, C.M.; Majumdar, D.

    1982-01-01

    Development of the first code version (MODO) of the Severe Core Damage Analysis Package (SCDAP) computer code is described, and calculations made with SCDAP/MODO are presented. The objective of this computer code development program is to develop a capability for analyzing severe disruption of a light water reactor core, including fuel and cladding liquefaction, flow, and freezing; fission product release; hydrogen generation; quenched-induced fragmentation; coolability of the resulting geometry; and ultimately vessel failure due to vessel-melt interaction. SCDAP will be used to identify the phenomena which control core behavior during a severe accident, to help quantify uncertainties in risk assessment analysis, and to support planning and evaluation of severe fuel damage experiments and data. SCDAP/MODO addresses the behavior of a single fuel bundle. Future versions will be developed with capabilities for core-wide and vessel-melt interaction analysis

  16. Civil protection and Damaging Hydrogeological Events: comparative analysis of the 2000 and 2015 events in Calabria (southern Italy

    Directory of Open Access Journals (Sweden)

    O. Petrucci

    2017-11-01

    Full Text Available Calabria (southern Italy is a flood prone region, due to both its rough orography and fast hydrologic response of most watersheds. During the rainy season, intense rain affects the region, triggering floods and mass movements that cause economic damage and fatalities. This work presents a methodological approach to perform the comparative analysis of two events affecting the same area at a distance of 15 years, by collecting all the qualitative and quantitative features useful to describe both rain and damage. The aim is to understand if similar meteorological events affecting the same area can have different outcomes in terms of damage. The first event occurred between 8 and 10 September 2000, damaged 109 out of 409 municipalities of the region and killed 13 people in a campsite due to a flood. The second event, which occurred between 30 October and 1 November 2015, damaged 79 municipalities, and killed a man due to a flood. The comparative analysis highlights that, despite the exceptionality of triggering daily rain was higher in the 2015 event, the damage caused by the 2000 event to both infrastructures and belongings was higher, and it was strongly increased due to the 13 flood victims. We concluded that, in the 2015 event, the management of pre-event phases, with the issuing of meteorological alert, and the emergency management, with the preventive evacuation of people in hazardous situations due to landslides or floods, contributed to reduce the number of victims.

  17. Event course analysis of core disruptive accidents; Ereignisablaufanalyse kernzerstoerender Unfaelle

    Energy Technology Data Exchange (ETDEWEB)

    Hering, W.; Homann, C.; Sengpiel, W.; Struwe, D.; Messainguiral, C.

    1995-08-01

    The theortical studies of the behavior of a PWR core in a meltdown accident are focused on hydrogen release, materials redistribution in the core area including forming of an oxide melt pool, quantity of melt and its composition, and temperatures attained by the RPV internals (esp. in the upper plenum) during the accident up to the time of melt relocation into the lower plenum. The calculations are done by the SCDAP/RELAP5 code. For its validation selected CORA results and Phebus FPTO results have been used. (orig.)

  18. An estimation of core damage frequency of a pressurized water reactor during midloop operation due to loss of residual heat removal

    International Nuclear Information System (INIS)

    Chao, C.C.; Chen, C.T.; Lee, M.

    1995-01-01

    The core damage frequency caused by loss of residual heat removal (RHR) events was assessed during midloop operation of a Westinghouse-designed three-loop pressurized water reactor. The assessment considers two types of outages (refueling and drained maintenance) and uses failure data collected specifically for shutdown condition. Event trees were developed for five categories of loss of RHR events. Human actions to mitigate the loss of RHR events were identified and human error probabilities were quantified using the human cognitive reliability (HCR) and the technique for human error rate prediction (THERP) models. The results showed that the core damage frequency caused by loss of RHR events during midloop operation was 3.4 x 10 -5 per year. The results also showed that the core damage frequency can be reduced significantly by removing a pressurizer safety valve before entering midloop operation. The establishment of reflux cooling, i.e., decay heat removal through the steam generator secondary side, also plays an important role in mitigating the loss of RHR events during midloop operation

  19. TMI-2 reactor-vessel head removal and damaged-core-removal planning

    International Nuclear Information System (INIS)

    Logan, J.A.; Hultman, C.W.; Lewis, T.J.

    1982-01-01

    A major milestone in the cleanup and recovery effort at TMI-2 will be the removal of the reactor vessel closure head, planum, and damaged core fuel material. The data collected during these operations will provide the nuclear power industry with valuable information on the effects of high-temperature-dissociated coolant on fuel cladding, fuel materials, fuel support structural materials, neutron absorber material, and other materials used in reactor structural support components and drive mechanisms. In addition, examination of these materials will also be used to determine accident time-temperature histories in various regions of the core. Procedures for removing the reactor vessel head and reactor core are presented

  20. Modeling and analysis framework for core damage propagation during flow-blockage-initiated accidents in the Advanced Neutron Source reactor at Oak Ridge National Laboratory

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.; Navarro-Valenti, S.; Georgevich, V.

    1995-01-01

    This paper describes modeling and analysis to evaluate the extent of core damage during flow blockage events in the Advanced Neutron Source (ANS) reactor planned to be built at ORNL. Damage propagation is postulated to occur from thermal conduction between dmaged and undamaged plates due to direct thermal contact. Such direct thermal contact may occur beause of fuel plate swelling during fission product vapor release or plate buckling. Complex phenomena of damage propagation were modeled using a one-dimensional heat transfer model. A parametric study was done for several uncertain variables. The study included investigating effects of plate contact area, convective heat transfer coefficient, thermal conductivity on fuel swelling, and initial temperature of the plate being contacted by the damaged plate. Also, the side support plates were modeled to account for their effects of damage propagation. Results provide useful insights into how variouss uncertain parameters affect damage propagation

  1. Comparison of advanced mid-sized reactors regarding passive features, core damage frequencies and core melt retention features

    International Nuclear Information System (INIS)

    Wider, H.

    2005-01-01

    New Light Water Reactors, whose regular safety systems are complemented by passive safety systems, are ready for the market. The special aspect of passive safety features is their actuation and functioning independent of the operator. They add significantly to reduce the core damage frequency (CDF) since the operator continues to play its independent role in actuating the regular safety devices based on modern instrumentation and control (I and C). The latter also has passive features regarding the prevention of accidents. Two reactors with significant passive features that are presently offered on the market are the AP1000 PWR and the SWR 1000 BWR. Their passive features are compared and also their core damage frequencies (CDF). The latter are also compared with those of a VVER-1000. A further discussion about the two passive plants concerns their mitigating features for severe accidents. Regarding core-melt retention both rely on in-vessel cooling of the melt. The new VVER-1000 reactor, on the other hand features a validated ex-vessel concept. (author)

  2. Preparations to load, transport, receive, and store the damaged TMI-2 [Three Mile Island] reactor core

    International Nuclear Information System (INIS)

    Reno, H.W.; Schmitt, R.C.; Quinn, G.J.; Ayers, A.L. Jr.; Lilburn, B.J. Jr.; Uhl, D.L.

    1986-03-01

    The March 1979 incident at the Three Mile Island Nuclear Power Station (TMI) which damaged the core of the Unit 2 reactor resulted in numerous scientific and technical challenges. Some of those challenges involve removing, packaging, and transporting the core debris to the Idaho National Engineering Laboratory (INEL) for storage, examination, and preparation for final disposal. This paper highlights preparations for transporting the core debris from TMI to INEL and receiving and storing that material at INEL. Issues discussed include interfacing of equipment and facilities at TMI, loading operations, transportation activities using a newly designed cask, receiving and storing operations at INEL, and criticality control during storage. Key to the transportation effort was designing, testing, fabricating, and licensing two rail casks which individually provide double containment of the damaged fuel. 27 figs

  3. Re criticality assessment following reactor core damage in Fukushima unit 2

    International Nuclear Information System (INIS)

    Jeong, Hae Sun; Song, Jin Ho; Park, Chang Je; Ha, Kwang Soon; Song, Yong Mann; Ryu, Eun Hyun

    2012-01-01

    Following the severe core damage accident at the Fukushima nuclear power plants (NPPs), many researchers have studied a possible Re criticality caused by core melting or corium. However, no one can accurately examine the internal conditions of the reactor vessel, and thus there have been different opinions from some organizations depending on their assumption and analysis methods. If there is a potential Re criticality in the reactor vessel, some counter plans for the accident management should be established to prevent and mitigate re criticality, and to return the plant to a safe and stable state. In this study, the criticality level following a severe core damage accident was first analyzed using the MCNPX 2.6.0 code. Based on this result, practical strategies in terms of accident management were obtained by charging soluble boron (H 3B O 3) into re flooded water

  4. Just and reasonable distribution of funds for limited damages in the event of nuclear disasters

    International Nuclear Information System (INIS)

    Schattke, H.

    1985-01-01

    A suggestion is made to make legal dispositions for the distribution of funds before a nuclear event. The concept incorporates the following material-legal elements: Proportionate reduction of damages compensation claims in case the funds for liability and coverage are insufficient; creation of reserve funds for late damage; legal preference of personal damage and only subsequent satisfaction of demand for compensation of nuclear industries. (orig.) [de

  5. A core hSSB1–INTS complex participates in the DNA damage response

    OpenAIRE

    Zhang, Feng; Ma, Teng; Yu, Xiaochun

    2013-01-01

    Human single-stranded DNA-binding protein 1 (hSSB1) plays an important role in the DNA damage response and the maintenance of genomic stability. It has been shown that the core hSSB1 complex contains hSSB1, INTS3 and C9orf80. Using protein affinity purification, we have identified integrator complex subunit 6 (INTS6) as a major subunit of the core hSSB1 complex. INTS6 forms a stable complex with INTS3 and hSSB1 both in vitro and in vivo. In this complex, INTS6 directly interacts with INTS3. I...

  6. Climate Change Risks – Methodological Framework and Case Study of Damages from Extreme Events in Cambodia

    DEFF Research Database (Denmark)

    Halsnæs, Kirsten; Kaspersen, Per Skougaard; Trærup, Sara Lærke Meltofte

    2016-01-01

    Climate change imposes some special risks on Least Developed Countries, and the chapter presents a methodological framework, which can be used to assess the impacts of key assumptions related to damage costs, risks and equity implications on current and future generations. The methodological...... framework is applied to a case study of severe storms in Cambodia based on statistical information on past storm events including information about buildings damaged and victims. Despite there is limited data available on the probability of severe storm events under climate change as well on the actual...... damage costs associated with the events in the case of Cambodia, we are using the past storm events as proxy data in a sensitivity analysis. It is here demonstrated how key assumptions on future climate change, income levels of victims, and income distribution over time, reflected in discount rates...

  7. Core damage frequency observations and insights of LWRs based on the IPEs

    Energy Technology Data Exchange (ETDEWEB)

    Dingman, S.E.; Camp, A.L. [Sandia National Labs., Albuquerque, NM (United States); Drouin, M.T. [and others

    1995-04-01

    Seventy-eight plants are expected to submit Individual Plant Examinations (IPEs) for severe accident vulnerabilities to the US Nuclear Regulatory Commission (NRC). The majority of the plants have elected to perform full Level 1 probabilistic risk assessments (PRAs) to meet the intent of the IPEs. Because of this, it is possible to compare the results from the IPE submittals to determine general observations and {open_quotes}lessons learned{close_quotes} from the IPEs. The IPE Insights Program is performing this evaluation, and preliminary results are presented in this paper. The core damage frequency and core damage sequences are identified and compared for pressurized water reactors and boiling water reactors. Examination of the results indicates that variations among plant results are due to a combination of actual plant design/operational features and analysis approaches. The findings are consistent with previous NRC studies, such as WASH-1400 and NUREG-1150.

  8. Drilling induced damage of core samples. Evidences from laboratory testing and numerical modelling

    International Nuclear Information System (INIS)

    Lanaro, Flavio

    2008-01-01

    Extensive sample testing in uniaxial and Brazilian test conditions were carried out for the Shobasama and MIU Research Laboratory Site (Gifu Pref., Japan). The compressive and tensile strength of the samples was observed to be negatively correlated to the in-situ stress components. Such correlation was interpreted as stress-release induced sample damage. Similar stress conditions were then numerically simulated by means of the BEM-DDM code FRACOD 2D in plane strain conditions. This method allows for explicitly consider the influence of newly initiated or propagating fractures on the stress field and deformation of the core during drilling process. The models show that already at moderate stress levels some fracturing of the core during drilling might occur leading to reduced laboratory strength of the samples. Sample damage maps were produced independently from the laboratory test results and from the numerical models and show good agreement with each other. (author)

  9. Core damage frequency observations and insights of LWRs based on the IPEs

    International Nuclear Information System (INIS)

    Dingman, S.E.; Camp, A.L.; Drouin, M.T.; Kolaczkowski, A.; Darby, J.; LaChance, J.L.; Yakle, J.

    1995-01-01

    Seventy-eight plants are expected to submit Individual Plant Examinations (IPEs) for severe accident vulnerabilities to the U.S. Nuclear Regulatory Commission (NRC). The majority of the plants have elected to perform full Level 1 probabilistic risk assessments (PRAs) to meet the intent of the IPES. Because of this, it is possible to compare the results from the IPE submittals to determine general observations and open-quotes lessons learnedclose quotes from the IPES. The IPE Insights Program is performing this evaluation, and preliminary results are presented in this paper. The core damage frequency and core damage sequences are identified and compared for pressurized water reactors and boiling water reactors. Examination of the results indicates that variations among plant results are due to a combination of actual plant design/operational features and analysis approaches. The findings are consistent with previous NRC studies, such as WASH-1400 and NUREG-1 150

  10. Visualization of Heat Transfer and Core Damage With RGUI 1.5

    International Nuclear Information System (INIS)

    Mesina, George L.

    2002-01-01

    Graphical User Interfaces (GUI) have become an integral and essential part of computer software. In the ever-changing world of computing, they provide the user with a valuable means to learn, understand, and use the application software while also helping applications adapt to and span different computing paradigms, such as different operating systems. For these reasons, GUI development for nuclear plant analysis programs has been ongoing for a decade and a half and much progress has been made. With the development of codes such as RELAP5-3D [1] and SCDAP/RELAP5 that have multi-dimensional modeling capability, it has become necessary to represent three-dimensional, calculated data. The RELAP5-3D Graphical User Interface (RGUI) [4] was designed specifically for this purpose. It reduces the difficulty of analyzing complex three-dimensional models and enhances the analysts' ability to recognize plant behavior visually. Previous versions of RGUI [5] focused on visualizing reactor coolant behavior during a simulated transient or accident. Recent work has extended RGUI to display two other phenomena, heat transfer and core damage. Heat transfer is depicted through the visualization of RELAP5-3D heat structures. Core damage is visualized by displaying fuel rods and other core structures in a reactor vessel screen. Conditions within the core are displayed via numerical results and color maps. These new features of RGUI 1.5 are described and illustrated. (authors)

  11. BUILDING DAMAGE ASSESSMENT AFTER EARTHQUAKE USING POST-EVENT LiDAR DATA

    Directory of Open Access Journals (Sweden)

    H. Rastiveis

    2015-12-01

    Full Text Available After an earthquake, damage assessment plays an important role in leading rescue team to help people and decrease the number of mortality. Damage map is a map that demonstrates collapsed buildings with their degree of damage. With this map, finding destructive buildings can be quickly possible. In this paper, we propose an algorithm for automatic damage map generation after an earthquake using post-event LiDAR Data and pre-event vector map. The framework of the proposed approach has four main steps. To find the location of all buildings on LiDAR data, in the first step, LiDAR data and vector map are registered by using a few number of ground control points. Then, building layer, selected from vector map, are mapped on the LiDAR data and all pixels which belong to the buildings are extracted. After that, through a powerful classifier all the extracted pixels are classified into three classes of “debris”, “intact building” and “unclassified”. Since textural information make better difference between “debris” and “intact building” classes, different textural features are applied during the classification. After that, damage degree for each candidate building is estimated based on the relation between the numbers of pixels labelled as “debris” class to the whole building area. Calculating the damage degree for each candidate building, finally, building damage map is generated. To evaluate the ability proposed method in generating damage map, a data set from Port-au-Prince, Haiti’s capital after the 2010 Haiti earthquake was used. In this case, after calculating of all buildings in the test area using the proposed method, the results were compared to the damage degree which estimated through visual interpretation of post-event satellite image. Obtained results were proved the reliability of the proposed method in damage map generation using LiDAR data.

  12. Field and laboratory investigations of coring-induced damage in core recovered from Marker Bed 139 at the waste isolation pilot plant underground facility

    International Nuclear Information System (INIS)

    Holcomb, D.J.; Zeuch, D.H.; Morin, K.; Hardy, R.; Tormey, T.V.

    1995-09-01

    A combined laboratory and field investigation was carried out to determine the extent of coring-induced damage done to samples cored from Marker Bed 139 at the WIPP site. Coring-induced damage, if present, has the potential to significantly change the properties of the material used for laboratory testing relative to the in situ material properties, resulting in misleading conclusions. In particular, connected, crack-like damage could make the permeability of cored samples orders of magnitude greater than the in situ permeabilities. Our approach compared in situ velocity and resistivity measurements with laboratory measurements of the same properties. Differences between in situ and laboratory results could be attributed to differences in the porosity due to cracks. The question of the origin of the changes could not be answered directly from the results of the measurements. Pre-existing cracks, held closed by the in situ stress, could open when the core was cut free, or new cracks could be generated by coring-induced damage. We used core from closely spaced boreholes at three orientations (0 degree, ±45 degrees relative to vertical) to address the origin of cracks. The absolute orientation of pre-existing cracks would be constant, independent of the borehole orientation. In contrast, cracks induced by coring were expected to show an orientation dependent on that of the source borehole

  13. Field and laboratory investigations of coring-induced damage in core recovered from Marker Bed 139 at the waste isolation pilot plant underground facility

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, D.J.; Zeuch, D.H.; Morin, K.; Hardy, R.; Tormey, T.V.

    1995-09-01

    A combined laboratory and field investigation was carried out to determine the extent of coring-induced damage done to samples cored from Marker Bed 139 at the WIPP site. Coring-induced damage, if present, has the potential to significantly change the properties of the material used for laboratory testing relative to the in situ material properties, resulting in misleading conclusions. In particular, connected, crack-like damage could make the permeability of cored samples orders of magnitude greater than the in situ permeabilities. Our approach compared in situ velocity and resistivity measurements with laboratory measurements of the same properties. Differences between in situ and laboratory results could be attributed to differences in the porosity due to cracks. The question of the origin of the changes could not be answered directly from the results of the measurements. Pre-existing cracks, held closed by the in situ stress, could open when the core was cut free, or new cracks could be generated by coring-induced damage. We used core from closely spaced boreholes at three orientations (0{degree}, {plus_minus}45{degrees} relative to vertical) to address the origin of cracks. The absolute orientation of pre-existing cracks would be constant, independent of the borehole orientation. In contrast, cracks induced by coring were expected to show an orientation dependent on that of the source borehole.

  14. Impact of Damaging Geo-Hydrological Events and Population Development in Calabria, Southern Italy

    Directory of Open Access Journals (Sweden)

    Maurizio Polemio

    2013-11-01

    Full Text Available Damaging geo-Hydrogeological Events (DHEs are defined as the occurrence of destructive phenomena (such as landslides and floods that can cause damage to people and goods during periods of bad weather. These phenomena should be analyzed together as they actually occur because their interactions can both amplify the damage and obstruct emergency management. The occurrence of DHEs depends on the interactions between climatic and geomorphological features: except for long-term climatic changes, these interactions can be considered constant, and for this reason, some areas are systematically affected. However, damage scenarios can change; events that occurred in the past could presently cause different effects depending on the modifications that occurred in the geographical distribution of vulnerable elements. We analyzed a catastrophic DHE that in 1951 affected an area 3700 km2 wide, located in Calabria (southern Italy, with four-day cumulative rainfall exceeding 300 mm and return periods of daily rain exceeding 500 Y. It resulted in 101 victims and 4500 homeless individuals. The probability that a similar event will happen again in the future is assessed using the return period of the triggering rainfall, whereas the different anthropogenic factors are taken into account by means of the population densities at the time of the event and currently. The result is a classification of regional municipalities according to the probability that events such as the one analyzed will occur again in the future and the possible effects of this event on the current situation.

  15. Issues and decisions for nuclear power plant management after fuel damage events

    International Nuclear Information System (INIS)

    1997-04-01

    Experience has shown that the on-site activities following an incident that results in severely damaged fuel at a nuclear power plant required extraordinary effort. Even in cases that are not extreme but in which fuel damage is greater than mentioned in the specifications for operation, the recovery will require extensive work. This publication includes information from several projects at the IAEA since 1989 that have resulted in a Technical Report, a TECDOC and a Workshop. While the initial purpose of the projects was focused on providing technical information transfer to the experts engaged in recovery work at the damaged unit of Chernobyl NPP, the results have led to a general approach to managing events in which there is substantial fuel damage. This TECDOC summarizes the work to focus on management issues that may be encountered in any such event whether small or large. 11 refs, 2 figs, 5 tabs

  16. Thermal behavior of molten corium during TMI-2 core relocation event

    International Nuclear Information System (INIS)

    Anderson, J.L.; Sienicki, J.J.

    1988-01-01

    During the TMI-2 accident, a pool of molten corium formed in the central region of the core and was contained by solidified crusts. Failure of the crust surrounding the molten material, at approximately 224 min, resulted in a relocation of an estimated 20-25 tons of molten corium through peripheral fuel assemblies in the east side of the vessel, as well as through the core barrel assembly (CBA) at the periphery of the core. This paper presents the results of an analyses carried out to investigate the thermal interactions of molten corium with the CBA structures during the relocation event. The principal objectives of the analyses are: (a) to assess the potential for relocation to take place through the CBA versus the flow of molten core material directly downward through the core via the fuel assemblies; and (b) to understand the distribution of prior molten corium observed during vessel defueling examinations. 5 refs., 1 fig

  17. A prediction and damage assessment model for snowmelt flood events in middle and high latitudes Region

    Science.gov (United States)

    Qiao, C.; Huang, Q.; Chen, T.; Zhang, X.

    2017-12-01

    In the context of global warming, the snowmelt flood events in the mountainous area of the middle and high latitudes are increasingly frequent and create severe casualties and property damages. Carrying out the prediction and risk assessment of the snowmelt flood is of great importance in the water resources management, the flood warning and prevention. Based on the remote sensing and GIS techniques, the relationships of the variables influencing the snowmelt flood such as the snow area, the snow depth, the air temperature, the precipitation, the land topography and land covers are analyzed and a prediction and damage assessment model for snowmelt floods is developed. This model analyzes and predicts the flood submerging area, flood depth, flood grade, and the damages of different underlying surfaces in the study area in a given time period based on the estimation of snowmelt amount, the snowmelt runoff, the direction and velocity of the flood. Then it was used to predict a snowmelt flood event in the Ertis River Basin in northern Xinjiang, China, during March and June, 2005 and to assess its damages including the damages of roads, transmission lines, settlements caused by the floods and the possible landslides using the hydrological and meteorological data, snow parameter data, DEM data and land use data. A comparison was made between the prediction results from this model and observation data including the flood measurement and its disaster loss data, which suggests that this model performs well in predicting the strength and impact area of snowmelt flood and its damage assessment. This model will be helpful for the prediction and damage assessment of snowmelt flood events in the mountainous area in the middle and high latitudes in spring, which has great social and economic significance because it provides a relatively reliable method for snowmelt flood prediction and reduces the possible damages caused by snowmelt floods.

  18. IAEA Regional Workshop on Development and Validation of EOP/AMG for Effective Prevention/Mitigation of Severe Core Damage

    International Nuclear Information System (INIS)

    1999-01-01

    Materials of the IAEA Regional Workshop contain 24 presented lectures. Authors deal with development and validation of emergency operating procedures as well as with accident management guidelines (EOP/AMG) for effective prevention and mitigation of severe core damage

  19. The use of historical data for the characterisation of multiple damaging hydrogeological events

    Directory of Open Access Journals (Sweden)

    O. Petrucci

    2003-01-01

    Full Text Available Landslides, floods and secondary floods (hereinafter called phenomena triggered by rainfall and causing extensive damage are reviewed in this paper. Damaging Hydrogeological Events (DHEs are defined as the occurrence of one or more simultaneous aforementioned phenomena. A method for the characterisation of DHEs based upon historic data is proposed. The method is aimed at assessing DHE-related hazard in terms of recurrence, severity, damage, and extent of the affected area. Using GIS, the DHEs historical and climatic data collection, the geomorphological and hydrogeological characterisation of the hit areas, the characterisation of induced damage, the evaluation of triggering rainfall return period and critical duration of each DHE were carried out. The approach was applied to a test site in Southern Italy (Calabria for validation purposes. A database was set up including data from 24 events which have occurred during an 80-year period. The spatial distribution of phenomena was analysed together with the return period of cumulative rainfall. The trend of the occurred phenomena was also compared with the climatic trend. Four main types of Damaging Hydrogeological Events were identified in the study area.

  20. Whole-core damage analysis of EBR-II driver fuel elements following SHRT program

    International Nuclear Information System (INIS)

    Chang, L.K.; Koenig, J.F.; Porter, D.L.

    1987-01-01

    In the Shutdown Heat Removal Testing (SHRT) program in EBR-II, fuel element cladding temperatures of some driver subassemblies were predicted to exceed temperatures at which cladding breach may occur. A whole-core thermal analysis of driver subassemblies was performed to determine the cladding temperatures of fuel elemnts, and these temperatures were used for fuel element damage calculation. The accumulated cladding damage of fuel element was found to be very small and fuel element failure resulting from SHRT transients is unlikely. No element breach was noted during the SHRT transients. The reactor was immediately restarted after the most severe SHRT transient had been completed and no driver fuel breach has been noted to date. (orig.)

  1. Recreational stimulants, herbal, and spice cannabis: The core psychobiological processes that underlie their damaging effects.

    Science.gov (United States)

    Parrott, Andrew C; Hayley, Amie C; Downey, Luke A

    2017-05-01

    Recreational drugs are taken for their positive mood effects, yet their regular usage damages well-being. The psychobiological mechanisms underlying these damaging effects will be debated. The empirical literature on recreational cannabinoids and stimulant drugs is reviewed. A theoretical explanation for how they cause similar types of damage is outlined. All psychoactive drugs cause moods and psychological states to fluctuate. The acute mood gains underlie their recreational usage, while the mood deficits on withdrawal explain their addictiveness. Cyclical mood changes are found with every central nervous system stimulant and also occur with cannabis. These mood state changes provide a surface index for more profound psychobiological fluctuations. Homeostatic balance is altered, with repetitive disturbances of the hypothalamic-pituitary-adrenal axis, and disrupted cortisol-neurohormonal secretions. Hence, these drugs cause increased stress, disturbed sleep, neurocognitive impairments, altered brain activity, and psychiatric vulnerability. Equivalent deficits occur with novel psychoactive stimulants such as mephedrone and artificial "spice" cannabinoids. These psychobiological fluctuations underlie drug dependency and make cessation difficult. Psychobiological stability and homeostatic balance are optimally restored by quitting psychoactive drugs. Recreational stimulants such as cocaine or MDMA (3.4-methylenedioxymethamphetamine) and sedative drugs such as cannabis damage human homeostasis and well-being through similar core psychobiological mechanisms. Copyright © 2017 John Wiley & Sons, Ltd.

  2. Consequence analysis of core damage states following severe accidents for the CANDU reactor design

    International Nuclear Information System (INIS)

    Wahba, N.N.; Kim, Y.T.; Lie, S.G.

    1997-01-01

    The analytical methodology used to evaluate severe accident sequences is described. The relevant thermal-mechanical phenomena and the mathematical approach used in calculating the timing of the accident progression and source term estimate are summarized. The postulated sever accidents analyzed, in general, mainly differ in the timing to reach and progress through each defined c ore damage state . This paper presents the methodology and results of the timing and steam discharge calculations as well as source term estimate out of containment for accident sequences classified as potentially leading to core disassembly following a small break loss-of-coolant accident (LOCA) scenario as a specific example. (author)

  3. CoreFlow: Enriching Bro security events using network traffic monitoring data

    NARCIS (Netherlands)

    Koning, R.; Buraglio, N.; de Laat, C.; Grosso, P.

    Attacks against network infrastructures can be detected by Intrusion Detection Systems (IDS). Still reaction to these events are often limited by the lack of larger contextual information in which they occurred. In this paper we present CoreFlow, a framework for the correlation and enrichment of IDS

  4. Delay-time distribution of core-collapse supernovae with late events resulting from binary interaction

    Science.gov (United States)

    Zapartas, E.; de Mink, S. E.; Izzard, R. G.; Yoon, S.-C.; Badenes, C.; Götberg, Y.; de Koter, A.; Neijssel, C. J.; Renzo, M.; Schootemeijer, A.; Shrotriya, T. S.

    2017-05-01

    Most massive stars, the progenitors of core-collapse supernovae, are in close binary systems and may interact with their companion through mass transfer or merging. We undertake a population synthesis study to compute the delay-time distribution of core-collapse supernovae, that is, the supernova rate versus time following a starburst, taking into account binary interactions. We test the systematic robustness of our results by running various simulations to account for the uncertainties in our standard assumptions. We find that a significant fraction, %, of core-collapse supernovae are "late", that is, they occur 50-200 Myr after birth, when all massive single stars have already exploded. These late events originate predominantly from binary systems with at least one, or, in most cases, with both stars initially being of intermediate mass (4-8 M⊙). The main evolutionary channels that contribute often involve either the merging of the initially more massive primary star with its companion or the engulfment of the remaining core of the primary by the expanding secondary that has accreted mass at an earlier evolutionary stage. Also, the total number of core-collapse supernovae increases by % because of binarity for the same initial stellar mass. The high rate implies that we should have already observed such late core-collapse supernovae, but have not recognized them as such. We argue that φ Persei is a likely progenitor and that eccentric neutron star - white dwarf systems are likely descendants. Late events can help explain the discrepancy in the delay-time distributions derived from supernova remnants in the Magellanic Clouds and extragalactic type Ia events, lowering the contribution of prompt Ia events. We discuss ways to test these predictions and speculate on the implications for supernova feedback in simulations of galaxy evolution.

  5. Failure Predictions for VHTR Core Components using a Probabilistic Contiuum Damage Mechanics Model

    Energy Technology Data Exchange (ETDEWEB)

    Fok, Alex

    2013-10-30

    The proposed work addresses the key research need for the development of constitutive models and overall failure models for graphite and high temperature structural materials, with the long-term goal being to maximize the design life of the Next Generation Nuclear Plant (NGNP). To this end, the capability of a Continuum Damage Mechanics (CDM) model, which has been used successfully for modeling fracture of virgin graphite, will be extended as a predictive and design tool for the core components of the very high- temperature reactor (VHTR). Specifically, irradiation and environmental effects pertinent to the VHTR will be incorporated into the model to allow fracture of graphite and ceramic components under in-reactor conditions to be modeled explicitly using the finite element method. The model uses a combined stress-based and fracture mechanics-based failure criterion, so it can simulate both the initiation and propagation of cracks. Modern imaging techniques, such as x-ray computed tomography and digital image correlation, will be used during material testing to help define the baseline material damage parameters. Monte Carlo analysis will be performed to address inherent variations in material properties, the aim being to reduce the arbitrariness and uncertainties associated with the current statistical approach. The results can potentially contribute to the current development of American Society of Mechanical Engineers (ASME) codes for the design and construction of VHTR core components.

  6. Damaging Hydrogeological Events: A Procedure for the Assessment of Severity Levels and an Application to Calabria (Southern Italy

    Directory of Open Access Journals (Sweden)

    Tommaso Caloiero

    2014-11-01

    Full Text Available A damaging hydrogeological event (DHE is characterized by two components: a rainfall event and a subsequent damage event, which is the result of floods and landslides triggered by rainfall. The characteristics of both events depend on climatic, geomorphological and anthropogenic factors. In this paper, a methodology to classify the severity of DHEs is presented. A chart which considers indicators of both the damage (Dscore and the daily rainfall (Rscore values recorded in the study area is proposed. According to the chart, the events are classified into four types: ordinary events, with low Dscore and Rscore values; extraordinary events, with high Rscore values but low Dscore values; catastrophic events, characterized by non-exceptional rainfall (low Rscore and severe damage (high Dscore; major catastrophic events, obtained by both high Dscore and Rscore values. Using this approach, the 2013 DHE that occurred in Calabria (Italy was classified as an ordinary event, when compared to the previous ones, even though the widespread diffusion of damage data induced the perception of high severity damage. The rainfall that triggered this event confirms the negative trend of heavy daily precipitation detected in Calabria, and the damage can be ascribed more to sub-daily than daily rainfall affecting urbanized flood-prone areas.

  7. Measurement of 3H in soil cores from the Hyrax Event (U3bh) subsidence crater

    International Nuclear Information System (INIS)

    Kreek, S.; Hudson, G.B.; Ruth, M.

    1996-01-01

    Core samples were collected from two boreholes drilled in the subsidence crater of the Hyrax event (U3bh). The moisture in the core samples was extracted via freeze drying and tritiw-n was measured in the extracted moisture via 'He accumulation mass spectrometry or liquid scintillation counting. Elevated tritium concentrations (IE4 - IE6 pCi/L extracted moisture as of the time of measurement) were observed in the extracted moisture from virtually all of the core samples with significant increases beginning at about 30 ft depth. No longer-lived fission products (144 Ce) or activation products ('OCo, 'Eu, 114 En) were observed by gamma-ray spectroscopy in a subset of the core samples. This likely indicates that a catastrophic failure of containment (if it occurred) did not release significant radioactivities to this shallow depth (30 ft). The presence of 'Cs at much greater depths (at sign 210 ft, 64 m) may indicate that gaseous and/or vapor products were released shortly after the Hyrax event to a depth of about 210 ft. The relatively shallow depth where the elevated tritium is observed makes highly improbable any significant linkage between the elevated tritium concentrations and a Hyrax event containment failure. This may indicate that an additional source of enriched 'H was introduced at this site

  8. Measurement of 3H in soil cores from the Hyrax Event (U3bh) subsidence crater

    Energy Technology Data Exchange (ETDEWEB)

    Kreek, S.; Hudson, G.B.; Ruth, M.

    1996-07-01

    Core samples were collected from two boreholes drilled in the subsidence crater of the Hyrax event (U3bh). The moisture in the core samples was extracted via freeze drying and tritiw-n was measured in the extracted moisture via `He accumulation mass spectrometry or liquid scintillation counting. Elevated tritium concentrations (IE4 - IE6 pCi/L extracted moisture as of the time of measurement) were observed in the extracted moisture from virtually all of the core samples with significant increases beginning at about 30 ft depth. No longer-lived fission products (144 Ce) or activation products (`OCo, `Eu, 114 En) were observed by gamma-ray spectroscopy in a subset of the core samples. This likely indicates that a catastrophic failure of containment (if it occurred) did not release significant radioactivities to this shallow depth (30 ft). The presence of `Cs at much greater depths (@210 ft, 64 m) may indicate that gaseous and/or vapor products were released shortly after the Hyrax event to a depth of about 210 ft. The relatively shallow depth where the elevated tritium is observed makes highly improbable any significant linkage between the elevated tritium concentrations and a Hyrax event containment failure. This may indicate that an additional source of enriched `H was introduced at this site.

  9. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal floods during mid-loop operations. Volume 4

    International Nuclear Information System (INIS)

    Kohut, P.

    1994-07-01

    The major objective of the Surry internal flood analysis was to provide an improved understanding of the core damage scenarios arising from internal flood-related events. The mean core damage frequency of the Surry plant due to internal flood events during mid-loop operations is 4.8E-06 per year, and the 5th and 95th percentiles are 2.2E-07 and 1.8E-05 per year, respectively. Some limited sensitivity calculations were performed on three plant improvement options. The most significant result involves modifications of intake-level structure on the canal, which reduced core damage frequency contribution from floods in mid-loop by about 75%

  10. Estimating shaking-induced casualties and building damage for global earthquake events: a proposed modelling approach

    Science.gov (United States)

    So, Emily; Spence, Robin

    2013-01-01

    Recent earthquakes such as the Haiti earthquake of 12 January 2010 and the Qinghai earthquake on 14 April 2010 have highlighted the importance of rapid estimation of casualties after the event for humanitarian response. Both of these events resulted in surprisingly high death tolls, casualties and survivors made homeless. In the Mw = 7.0 Haiti earthquake, over 200,000 people perished with more than 300,000 reported injuries and 2 million made homeless. The Mw = 6.9 earthquake in Qinghai resulted in over 2,000 deaths with a further 11,000 people with serious or moderate injuries and 100,000 people have been left homeless in this mountainous region of China. In such events relief efforts can be significantly benefitted by the availability of rapid estimation and mapping of expected casualties. This paper contributes to ongoing global efforts to estimate probable earthquake casualties very rapidly after an earthquake has taken place. The analysis uses the assembled empirical damage and casualty data in the Cambridge Earthquake Impacts Database (CEQID) and explores data by event and across events to test the relationships of building and fatality distributions to the main explanatory variables of building type, building damage level and earthquake intensity. The prototype global casualty estimation model described here uses a semi-empirical approach that estimates damage rates for different classes of buildings present in the local building stock, and then relates fatality rates to the damage rates of each class of buildings. This approach accounts for the effect of the very different types of buildings (by climatic zone, urban or rural location, culture, income level etc), on casualties. The resulting casualty parameters were tested against the overall casualty data from several historical earthquakes in CEQID; a reasonable fit was found.

  11. Catalogue of methods, tools and techniques for recovery from fuel damage events

    International Nuclear Information System (INIS)

    1991-10-01

    On the basis of the recommendations of the Advisory Group Meeting on Main Principles of Safe Management of Severely Damaged Nuclear Fuel and other Accident Generated Waste, held from 13 to 16 November 1989, the IAEA initiated a programme in 1990 to collect technical information on special tools and methods to deal with circumstances beyond the normal design basis of fuel damage. A Questionnaire was sent out to solicit information from the Member States and organizations which might have experience in this field. The responses to the Questionnaire were discussed at a Consultants Meeting and at an Advisory Group Meeting during 1990. The aim of this document is to disseminate the experience gained in Member States serving Article 5 of the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency and also filling a potential void in response to fuel damage events of less severe magnitude

  12. Documentation of damage events concerning geothermal probes; Dokumentation von Schadensfaellen bei Erdwaermesonden

    Energy Technology Data Exchange (ETDEWEB)

    Bassetti, S.; Rohner, E.; Signorelli, S. [Geowatt AG, Zuerich (Switzerland); Matthey, B. [Ingenieurs-Conseils SA, Montezillon (Switzerland)

    2006-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at the various faults and damages encountered when geothermal probes are inappropriately used. The various fault conditions dealt with include: Connection of additional users, incorrect determination of the heat demand, incorrect thermal values for the subsoil, under-dimensioning of the bore-hole heat exchanger (BHE), neglecting the effects of interaction, incorrect or missing grouting of the BHE, incorrect control of the heat pump, incorrect hydraulics and leakage. In this report examples of frequently-noted damage events and the corrections necessary are presented. For some cases, the reason for the damage is additionally illustrated by a comparison with simulation results. Finally, tips for the professional planning and construction of bore-hole heat exchanger systems are presented.

  13. Track structure model for damage to mammalian cell cultures during solar proton events

    Science.gov (United States)

    Cucinotta, F. A.; Wilson, J. W.; Townsend, L. W.; Shinn, J. L.; Katz, R.

    1992-01-01

    Solar proton events (SPEs) occur infrequently and unpredictably, thus representing a potential hazard to interplanetary space missions. Biological damage from SPEs will be produced principally through secondary electron production in tissue, including important contributions due to delta rays from nuclear reaction products. We review methods for estimating the biological effectiveness of SPEs using a high energy proton model and the parametric cellular track model. Results of the model are presented for several of the historically largest flares using typical levels and body shielding.

  14. The IPE Database: providing information on plant design, core damage frequency and containment performance

    International Nuclear Information System (INIS)

    Lehner, J.R.; Lin, C.C.; Pratt, W.T.; Su, T.; Danziger, L.

    1996-01-01

    A database, called the IPE Database has been developed that stores data obtained from the Individual Plant Examinations (IPEs) which licensees of nuclear power plants have conducted in response to the Nuclear Regulatory Commission's (NRC) Generic Letter GL88-20. The IPE Database is a collection of linked files which store information about plant design, core damage frequency (CDF), and containment performance in a uniform, structured way. The information contained in the various files is based on data contained in the IPE submittals. The information extracted from the submittals and entered into the IPE Database can be manipulated so that queries regarding individual or groups of plants can be answered using the IPE Database

  15. Estimation of irradiation-induced material damage measure of FCM fuel in LWR core

    International Nuclear Information System (INIS)

    Lee, Kyung-Hoon; Lee, Chungchan; Park, Sang-Yoon; Cho, Jin-Young; Chang, Jonghwa; Lee, Won Jae

    2014-01-01

    An irradiation-induced material damage measure on tri-isotropic (TRISO) multi-coating layers of fully ceramic micro-encapsulated (FCM) fuel to replace conventional uranium dioxide (UO 2 ) fuel for existing light water reactors (LWRs) has been estimated using a displacement per atom (DPA) cross section for a FCM fuel performance analysis. The DPA cross sections in 47 and 190 energy groups for both silicon carbide (SiC) and graphite are generated based on the molecular dynamics simulation by SRIM/TRIM. For the selected FCM fuel assembly design with FeCrAl cladding, a core depletion analysis was carried out using the DeCART2D/MASTER code system with the prepared DPA cross sections to evaluate the irradiation effect in the Korean OPR-1000. The DPA of the SiC and IPyC coating layers is estimated by comparing the discharge burnup obtained from the MASTER calculation with the burnup-dependent DPA for each coating layer calculated using DeCART2D. The results show that low uranium loading and hardened neutron spectrum compared to that of high temperature gas-cooled reactor (HTGR) result in high discharge burnup and high fast neutron fluence. In conclusion, it can be seen that the irradiation-induced material damage measure is noticeably increased under LWR operating conditions compared to HTGRs. (author)

  16. [Prevalence of target organ damage and factors associated with cardiovascular events in subjects with refractory hypertension].

    Science.gov (United States)

    Armario, Pedro; Oliveras, Anna; Hernández Del Rey, Raquel; Poch, Esteban; Larrouse, María; Roca-Cusachs, Alex; de la Sierra, Alejandro

    2009-06-27

    To asses the prevalence of target organ damage (TOD) and factors associated with cardiovascular events in subjects with refractory hypertension. Cross-sectional study of 146 patients with clinical diagnosis of refractory hypertension. TOD was defined as the presence of microalbuminuria (MA), renal failure (RF), left ventricular hypertrophy (LVH) or left atrial enlargement (LAE). Cardiovascular events were defined as the antecedent of stroke, coronary heart disease, heart failure or peripheral arterial disease. 24-h ambulatory blood pressure monitoring was (ABPM) performed with a validated Spacelabs 90207. The prevalence of LVH was 62.3%, and LAE was observed in 27.7% of the subjects. The prevalence of RF was 28.1% and MA was found in 41,4%. An association between MA and LVH was observed. After adjusting by age, the urinary albumin excretion (UAE) correlated with clinical blood pressure (BP) and BP during 24-h ABPM, whereas LVMI correlated with ambulatory BP but not with clinical BP. The prevalence of previous cardiovascular events was 22% and in the multivariate regression analysis, UAE was the only independent factor associated with the antecedent of cardiovascular events. In subjects with refractory hypertension, the prevalence of TOD was high, and an association between heart and renal organ damage was observed. UAE was independently associated with the antecedent of cardiovascular disease.

  17. DNA damage and cell cycle events implicate cerebellar dentate nucleus neurons as targets of Alzheimer's disease

    Directory of Open Access Journals (Sweden)

    Yang Yan

    2010-12-01

    Full Text Available Abstract Background Although the cerebellum is considered to be predominantly involved in fine motor control, emerging evidence documents its participation in language, impulsive behavior and higher cognitive functions. While the specific connections of the cerebellar deep nuclei (CDN that are responsible for these functions are still being worked out, their deficiency has been termed "cerebellar cognitive affective syndrome" - a syndrome that bears a striking similarity to many of the symptoms of Alzheimer's disease (AD. Using ectopic cell cycle events and DNA damage markers as indexes of cellular distress, we have explored the neuropathological involvement of the CDN in human AD. Results We examined the human cerebellar dentate nucleus in 22 AD cases and 19 controls for the presence of neuronal cell cycle events and DNA damage using immunohistochemistry and fluorescence in situ hybridization. Both techniques revealed several instances of highly significant correlations. By contrast, neither amyloid plaque nor neurofibrillary tangle pathology was detected in this region, consistent with previous reports of human cerebellar pathology. Five cases of early stage AD were examined and while cell cycle and DNA damage markers were well advanced in the hippocampus of all five, few indicators of either cell cycle events (1 case or a DNA damage response (1 case were found in CDN. This implies that CDN neurons are most likely affected later in the course of AD. Clinical-pathological correlations revealed that cases with moderate to high levels of cell cycle activity in their CDN are highly likely to show deficits in unorthodox cerebellar functions including speech, language and motor planning. Conclusion Our results reveal that the CDN neurons are under cellular stress in AD and suggest that some of the non-motor symptoms found in patients with AD may be partly cerebellar in origin.

  18. Characterization of the Fault Core and Damage Zone of the Borrego Fault, 2010 M7.2 Rupture

    Science.gov (United States)

    Dorsey, M. T.; Rockwell, T. K.; Girty, G.; Ostermeijer, G.; Mitchell, T. M.; Fletcher, J. M.

    2017-12-01

    We collected a continuous sample of the fault core and 23 samples of the damage zone out to 52 m across the rupture trace of the 2010 M7.2 El Mayor-Cucapa earthquake to characterize the physical damage and chemical transformations associated with this active seismic source. In addition to quantifying fracture intensity from macroscopic analysis, we cut a continuous thin section through the fault core and from various samples in the damage zone, and ran each sample for XRD analyses for clay mineralogy, XRF for bulk geochemical analyses, and bulk and grain density from which porosity and volumetric strain were derived. The parent rock is a hydrothermally-altered biotite tonalite, with biotite partially altered to chlorite. The presence of epidote with chlorite suggests that these rocks were subjected to relatively high temperatures of 300-400° C. Adjacent to the outermost damage zone is a chaotic breccia zone with distinct chemical and physical characteristics, indicating possible connection to an ancestral fault to the southwest. The damage zone consists of an outer zone of protocataclasite, which grades inward towards mesocataclasite with seams of ultracataclasite. The fault core is anomalous in that it is largely composed of a sliver of marble that has been translated along the fault, so direct comparison with the damage zone is impaired. From collected data, we observe that chloritization increases into the breccia and damage zones, as does the presence of illite. Porosity reaches maximum values in the damage zone adjacent to the core, and closely follows trends in fracture intensity. Statistically significant gains in Mg, Na, K, Mn, and total bulk mass occurred within the inner damage zone, with losses of Ca and P mass, which led to the formation of chlorite and albite. The outer damage zone displays gains in Mg and Na mass with losses in Ca and P mass. The breccia zone shows gains in mass of Mg and Mn and loss in total bulk mass. A gain in LOI in both the

  19. A backward method to estimate the Dai-ichi reactor core damage using radiation exposure in the environment

    International Nuclear Information System (INIS)

    PM Udiyani; S Kuntjoro; S Widodo

    2016-01-01

    The Fukushima accident resulted in the melting of the reactor core due to loss of supply of coolant when the reactor stopped from operating conditions. The earthquake and tsunami caused loss of electricity due to the flooding that occurred in the reactor. The absence of the coolant supply after reactor shutdown resulted in heat accumulation, causing the temperature of the fuel to rise beyond its melting point. In the early stages of the accident, operator could not determine the severity of the accident and the percentage of the reactor core damaged. The available data was based on the radiation exposure in the environment that was reported by the authorities. The aim of this paper is to determine the severity of the conditions in the reactor core based on the radiation doses measured in the environment. The method is performed by backward counting based on the measuring radiation exposure and radionuclides releases source term. The calculation was performed by using the PC-COSYMA code. The results showed that the core damage fraction at Dai-ichi Unit 1 was 70%, and the resulting individual effective dose in the exclusion area is 401 mSv, while the core damage fraction at Unit 2 was 30%, and the resulting individual effective dose was 9.1 mSv, while for Unit 3, the core damage fraction was 25% for an individual effective dose of 92.2 mSv. The differences between the results of the calculation for estimation of core damage proposed in this paper with the previously reported results is probably caused by the applied model for assessment, differences in postulations and assumptions, and the incompleteness of the input data. This difference could be reduced by performing calculations and simulations for more varied assumptions and postulations. (author)

  20. Managing satisfaction in cultural events: Exploring the role of core and peripheral product

    Directory of Open Access Journals (Sweden)

    Manuel Cuadrado-García

    2017-01-01

    Full Text Available This paper measures satisfaction with a cultural event following an innovative approach by differentiating between the art form itself (core product and the main attributes connected with it (augmented product. 122 individuals (out of 820 visitors were interviewed on their overall satisfaction and on different aspects of their visiting experience. Multivariate techniques such as ANOVA, principal component factor analysis and regression were performed to analyse the data. Results show the importance of both the core and the peripheral product in measuring satisfaction with a cultural event, thereby highlighting their importance for product management in the arts. The small sample, the specificity of the data and the bias of the distribution have prevented further multivariate analysis. A future area of research is on antecedents to customer satisfaction in the arts field. The contribution of peripheral elements to satisfaction should not be underestimated. Despite artists’ freedom to produce the work of art, a series of peripheral elements should be designed along with the other variables of the marketing mix in order to adapt and differentiate the artistic production to the target audience. This paper contributes a different perspective to measuring satisfaction in the arts context while considering the role of the core product and its peripherals.

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

    International Nuclear Information System (INIS)

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

    1994-06-01

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

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

    International Nuclear Information System (INIS)

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

    1994-06-01

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

  3. Damaging events along roads during bad weather periods: a case study in Calabria (Italy

    Directory of Open Access Journals (Sweden)

    O. Petrucci

    2012-02-01

    Full Text Available The study focuses on circumstances that affect people during periods of bad weather conditions characterised by winds, rainfall, landslides, flooding, and storm surges. A methodological approach and its application to a study area in southern Italy are presented here. A 10-yr database was generated by mining data from a newspaper. Damaging agents were sorted into five types: flood, urban flooding, landslide, wind, and storm surge. Damage to people occurred in 126 cases, causing 13 victims, 129 injured and about 782 people involved but not injured.

    For cases of floods, urban flooding and landslides, the analysis does not highlight straightforward relationships between rainfall and damage to people, even if the events showed different features according to the months of occurrence. The events occurring between May and October were characterised by concentrated and intense rainfall, and between May and July, the highest values of hourly (103 mm on the average and monthly rainfall (114 mm on the average were recorded. Urban flooding and flash floods were the most common damaging agents: injured, involved people and more rarely, cases with victims were reported.

    Between November and April, the highest number of events was recorded. Rainfall presented longer durations and hourly and sub-hourly rainfall were lower than those recorded between May and October. Landslides were the most frequent damaging agents but the highest number of cases with victims, which occurred between November and January, were mainly related to floods and urban flooding.

    Motorists represent the totality of the victims; 84% of the people were injured and the whole of people involved. All victims were men, and the average age was 43 yr. The primary cause of death was drowning caused by floods, and the second was trauma suffered in car accidents caused by urban flooding. The high number of motorists rescued in submerged cars reveals an underestimation of

  4. Damaging events along roads during bad weather periods: a case study in Calabria (Italy)

    Science.gov (United States)

    Petrucci, O.; Pasqua, A. A.

    2012-02-01

    The study focuses on circumstances that affect people during periods of bad weather conditions characterised by winds, rainfall, landslides, flooding, and storm surges. A methodological approach and its application to a study area in southern Italy are presented here. A 10-yr database was generated by mining data from a newspaper. Damaging agents were sorted into five types: flood, urban flooding, landslide, wind, and storm surge. Damage to people occurred in 126 cases, causing 13 victims, 129 injured and about 782 people involved but not injured. For cases of floods, urban flooding and landslides, the analysis does not highlight straightforward relationships between rainfall and damage to people, even if the events showed different features according to the months of occurrence. The events occurring between May and October were characterised by concentrated and intense rainfall, and between May and July, the highest values of hourly (103 mm on the average) and monthly rainfall (114 mm on the average) were recorded. Urban flooding and flash floods were the most common damaging agents: injured, involved people and more rarely, cases with victims were reported. Between November and April, the highest number of events was recorded. Rainfall presented longer durations and hourly and sub-hourly rainfall were lower than those recorded between May and October. Landslides were the most frequent damaging agents but the highest number of cases with victims, which occurred between November and January, were mainly related to floods and urban flooding. Motorists represent the totality of the victims; 84% of the people were injured and the whole of people involved. All victims were men, and the average age was 43 yr. The primary cause of death was drowning caused by floods, and the second was trauma suffered in car accidents caused by urban flooding. The high number of motorists rescued in submerged cars reveals an underestimation of danger in the case of floods, often

  5. Multi-core events in cosmic-ray induced interactions with lead at around 10 TeV

    International Nuclear Information System (INIS)

    Amato, N.; Arata, N.

    1989-01-01

    The analysis is made on the cosmic-ray induced interactions with lead at around 10 TeV on the basis of emulsion chamber data at Chacaltaya. A special attention is paid to the events detected as multi-cores under the spatial resolution of a few tens of microns. The observation of six double-core events and two triple-core events with the average invariant mass of 1.8 GeV/c 2 leads to the estimation on production frequency of such multicores as about 5% at 10 TeV at the atmospheric depth 540 gr/cm 2 . (author)

  6. The external costs of low probability-high consequence events: Ex ante damages and lay risks

    International Nuclear Information System (INIS)

    Krupnick, A.J.; Markandya, A.; Nickell, E.

    1994-01-01

    This paper provides an analytical basis for characterizing key differences between two perspectives on how to estimate the expected damages of low probability - high consequence events. One perspective is the conventional method used in the U.S.-EC fuel cycle reports [e.g., ORNL/RFF (1994a,b]. This paper articulates another perspective, using economic theory. The paper makes a strong case for considering this, approach as an alternative, or at least as a complement, to the conventional approach. This alternative approach is an important area for future research. I Interest has been growing worldwide in embedding the external costs of productive activities, particularly the fuel cycles resulting in electricity generation, into prices. In any attempt to internalize these costs, one must take into account explicitly the remote but real possibilities of accidents and the wide gap between lay perceptions and expert assessments of such risks. In our fuel cycle analyses, we estimate damages and benefits' by simply monetizing expected consequences, based on pollution dispersion models, exposure-response functions, and valuation functions. For accidents, such as mining and transportation accidents, natural gas pipeline accidents, and oil barge accidents, we use historical data to estimate the rates of these accidents. For extremely severe accidents--such as severe nuclear reactor accidents and catastrophic oil tanker spills--events are extremely rare and they do not offer a sufficient sample size to estimate their probabilities based on past occurrences. In those cases the conventional approach is to rely on expert judgments about both the probability of the consequences and their magnitude. As an example of standard practice, which we term here an expert expected damage (EED) approach to estimating damages, consider how evacuation costs are estimated in the nuclear fuel cycle report

  7. The external costs of low probability-high consequence events: Ex ante damages and lay risks

    Energy Technology Data Exchange (ETDEWEB)

    Krupnick, A J; Markandya, A; Nickell, E

    1994-07-01

    This paper provides an analytical basis for characterizing key differences between two perspectives on how to estimate the expected damages of low probability - high consequence events. One perspective is the conventional method used in the U.S.-EC fuel cycle reports [e.g., ORNL/RFF (1994a,b]. This paper articulates another perspective, using economic theory. The paper makes a strong case for considering this, approach as an alternative, or at least as a complement, to the conventional approach. This alternative approach is an important area for future research. I Interest has been growing worldwide in embedding the external costs of productive activities, particularly the fuel cycles resulting in electricity generation, into prices. In any attempt to internalize these costs, one must take into account explicitly the remote but real possibilities of accidents and the wide gap between lay perceptions and expert assessments of such risks. In our fuel cycle analyses, we estimate damages and benefits' by simply monetizing expected consequences, based on pollution dispersion models, exposure-response functions, and valuation functions. For accidents, such as mining and transportation accidents, natural gas pipeline accidents, and oil barge accidents, we use historical data to estimate the rates of these accidents. For extremely severe accidents--such as severe nuclear reactor accidents and catastrophic oil tanker spills--events are extremely rare and they do not offer a sufficient sample size to estimate their probabilities based on past occurrences. In those cases the conventional approach is to rely on expert judgments about both the probability of the consequences and their magnitude. As an example of standard practice, which we term here an expert expected damage (EED) approach to estimating damages, consider how evacuation costs are estimated in the nuclear fuel cycle report.

  8. Not my future? Core values and the neural representation of future events.

    Science.gov (United States)

    Brosch, Tobias; Stussi, Yoann; Desrichard, Olivier; Sander, David

    2018-06-01

    Individuals with pronounced self-transcendence values have been shown to put greater weight on the long-term consequences of their actions when making decisions. Using functional magnetic resonance imaging, we investigated the neural mechanisms underlying the evaluation of events occurring several decades in the future as well as the role of core values in these processes. Thirty-six participants viewed a series of events, consisting of potential consequences of climate change, which could occur in the near future (around 2030), and thus would be experienced by the participants themselves, or in the far future (around 2080). We observed increased activation in anterior VMPFC (BA11), a region involved in encoding the personal significance of future events, when participants were envisioning far future events, demonstrating for the first time that the role of the VMPFC in future projection extends to the time scale of decades. Importantly, this activation increase was observed only in participants with pronounced self-transcendence values measured by self-report questionnaire, as shown by a statistically significant interaction of temporal distance and value structure. These findings suggest that future projection mechanisms are modulated by self-transcendence values to allow for a more extensive simulation of far future events. Consistent with this, these participants reported similar concern ratings for near and far future events, whereas participants with pronounced self-enhancement values were more concerned about near future events. Our findings provide a neural substrate for the tendency of individuals with pronounced self-transcendence values to consider the long-term consequences of their actions.

  9. Sensitivity Analysis of Core Damage by Loss of Auxiliary Feed Water during the Extended Loss of All AC Power

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Woo Jae; Chung, Soon Il; Hwang, Su Hyun; Lee, Kyung Jin; Lee, Byung Chul [FNC Tech., Yongin (Korea, Republic of); Yun, Duk Joo; Lee, Seung Chan [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

    2015-10-15

    In this study, the reactor core damage time for OPR1000 type Nuclear Power Plant (NPP) was analyzed to develop a strategy to handle ELAP and to apply to the EOP. The reactor core damage time in the ELAP condition was calculated according to the time of Auxiliary Feedwater (AFW) loss. Fukushima accident was caused by long hours of Station Black Out (SBO) caused by natural disaster beyond Design Based Accident (DBA) criteria. It led to the reactor core damage. After the accident, the regulatory authorities of each country (Japan, US, EU, IAEA, and etc.) recommended developing the necessary systems and strategies in order to cover up the Extended Loss of All AC Power (ELAP) such as one occurred in the Fukushima accident. And the need of procedure or guideline to cope with ELAP has been raised through the stress test for Wolsong Nuclear Power Plant unit 1. Current Emergency Operating Procedures (EOP) used in domestic nuclear power plant are seemed to be insufficient to cope with ELAP. Therefore, it has been required to be improved. As the result, the time of AFW loss in the ELAP condition influences greatly on core damage time.

  10. Revisiting the 1993 historical extreme precipitation and damaging flood event in Central Nepal

    Science.gov (United States)

    Marahatta, S.; Adhikari, L.; Pokharel, B.

    2017-12-01

    Nepal is ranked the fourth most climate-vulnerable country in the world and it is prone to different weather-related hazards including droughts, floods, and landslides [Wang et al., 2013; Gillies et al., 2013]. Although extremely vulnerable to extreme weather events, there are no extreme weather warning system established to inform public in Nepal. Nepal has witnessed frequent drought and flood events, however, the extreme precipitation that occurred on 19-20 July 1993 created a devastating flood and landslide making it the worst weather disaster in the history of Nepal. During the second week of July, Nepal and northern India experienced abnormal dry condition due to the shifting of the monsoon trough to central India. The dry weather changed to wet when monsoon trough moved northward towards foothills of the Himalayas. Around the same period, a low pressure center was located over the south-central Nepal. The surface low was supported by the mid-, upper-level shortwave and cyclonic vorticity. A meso-scale convective system created record breaking one day rainfall (540 mm) in the region. The torrential rain impacted the major hydropower reservoir, Bagmati barrage in Karmaiya and triggered many landslides and flash floods. The region had the largest hydropower (Kulekhani hydropower, 92 MW) of the country at that time and the storm event deposited extremely large amount of sediments that reduced one-fourth (4.8 million m3) of reservoir dead storage (12 million m3). The 1-in-1000 years flood damaged the newly constructed barrage and took more than 700 lives. Major highways were damaged cutting off supply of daily needed goods, including food and gas, in the capital city, Kathmandu, for more than a month. In this presentation, the meteorological conditions of the extreme event will be diagnosed and the impact of the sedimentation due to the flood on Kulekhani reservoir and hydropower generation will be discussed.

  11. IPE Data Base: Plant design, core damage frequency and containment performance information

    International Nuclear Information System (INIS)

    Lehner, J.; Lin, C.C.; Pratt, W.T.; Su, T.; Danziger, L.

    1995-01-01

    This data base stores data obtained from the Individual Plant Examinations (IPEs) which licensees of nuclear power plants have conducted in response to NRC's Generic Letter GL88-20. The IPE Data Base is a collection of linked files which store information about plant design, core damage frequency, and containment performance in a uniform, structured way. The information contined in the various files is based on data contained in the IPE submittals. The information extracted from the submittals and entered into the IPE Data Base can be maniulated so that queries regarding individual or groups of plants can be answered using the IPE Data Base. The IPE Data Base supports detailed inquiries into the characteristics of individual plants or classes of plants. Progress has been made on the IPE Data Base and it is largely complete. Recent focus has been the development of a user friendly version which is menu driven and allows the user to ask queries of varying complexity easily, without the need to become familiar with particular data base formats or conventions such as those of DBase IV or Microsoft Access. The user can obtain the information he desired by quickly moving through a series of on-screen menus and ''clicking'' on appropriate choices. In this way even a first time user can benefit from the large amount of information stored in the IPE Data Base without the need of a learning period

  12. Observations of localised dielectric excitations, secondary events and ionisation damage by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Howie, A.

    1988-01-01

    In the scanning transmission electron microscope (STEM) a high intensity /approximately/0.5nm diameter, probe of 100 keV electrons is formed. This can be positioned to collect energy loss spectra from surfaces, interfaces, small spheres or other particles at controlled values of impact parameter or can be scanned across the object (usually a thin film) to produce high resolution images formed from a variety of signals - small angle or large angle (Z contrast) elastic scattering, inelastic scattering (both valence and core losses), secondary electron emission and x-ray or optical photon emission. The high spatial resolution achievable in a variety of simple structures raises many unsolved theoretical problems concerning the generation, propagation and decay of excitations in inhomogeneous media. These range from quite well posed problems in the mathematical physics of dielectric excitation to problems of plasmon propagation and rather more exotic and less well understood problems of radiation damage. 15 refs., 4 figs

  13. FANCI Regulates Recruitment of the FA Core Complex at Sites of DNA Damage Independently of FANCD2.

    Directory of Open Access Journals (Sweden)

    Maria Castella

    2015-10-01

    Full Text Available The Fanconi anemia (FA-BRCA pathway mediates repair of DNA interstrand crosslinks. The FA core complex, a multi-subunit ubiquitin ligase, participates in the detection of DNA lesions and monoubiquitinates two downstream FA proteins, FANCD2 and FANCI (or the ID complex. However, the regulation of the FA core complex itself is poorly understood. Here we show that the FA core complex proteins are recruited to sites of DNA damage and form nuclear foci in S and G2 phases of the cell cycle. ATR kinase activity, an intact FA core complex and FANCM-FAAP24 were crucial for this recruitment. Surprisingly, FANCI, but not its partner FANCD2, was needed for efficient FA core complex foci formation. Monoubiquitination or ATR-dependent phosphorylation of FANCI were not required for the FA core complex recruitment, but FANCI deubiquitination by USP1 was. Additionally, BRCA1 was required for efficient FA core complex foci formation. These findings indicate that FANCI functions upstream of FA core complex recruitment independently of FANCD2, and alter the current view of the FA-BRCA pathway.

  14. Parameters affecting of Akkuyu’s safety assessment for severe core damages

    Directory of Open Access Journals (Sweden)

    Kavun Yusuf

    2015-01-01

    Full Text Available We have looked at all past core meltdowns (Three Mile Island, Chernobyl and Fukushima incidents and postulated the fourth one might be taking place in the future most probably in a newly built reactors anywhere of the earth in any type of NPP. The probability of this observation is high considering the nature of the machine and human interaction. Operation experience is a very significant parameter as well as the safety culture of the host nation. The concerns is not just a lack of experience with industry with the new comers, but also the infrastructure and established institutions who will be dealing with the Emergencies. Lack of trained and educated Emergency Response Organizations (ERO is a major concern. The culture on simple fire drills even makes the difference when a severe condition occurs in the industry. The study assumes the fourth event will be taking place at the Akkuyu NGS and works backwards as required by the “what went wrong ” scenarios and comes up with interesting results. The differences studied in depth to determine the impact to the severe accidents. The all four design have now core catchers. We have looked at the operator errors’like in TMI; Operator errors combined with design deficiencies(like in Chernobyl and natural disasters( like in Fukushima and found operator errors to be more probable event on the Akkuyu’s postulated next incident. With respect to experiences of the operators we do not have any data except for long and successful operating history of the Soviet design reactors up until the Chernobyl incident. Since the Akkuyu will be built, own and operated by the Russians we have found no alarming concerns at the moment. At the moment, there is no body be able to operate those units in Turkey. Turkey is planning to build the required manpower during the transition period. The resolution of the observed parameters lies to work and educate, train of the host nation and exercise together.

  15. Effects of damaging hydrogeological events on people throughout 15 years in a Mediterranean region

    Directory of Open Access Journals (Sweden)

    L. Aceto

    2017-07-01

    Full Text Available Damaging Hydrogeological Events (DHE are defined as rainy periods during which landslides and floods can damage people. The paper investigated the effects of DHE on people living in Calabria (southern Italy in the period 2000–2014, using data coming from the systematic survey of regional newspapers. Data about fatalities, people injured and people involved (not killed neither hurt were stored in the database named PEOPLE, made of three sections: (1 event identification, (2 victim-event interaction, (3 effects on people. The outcomes highlighted vulnerability factors related to gender and age: males were killed more frequently (75 % than females (25 %, and fatalities were older (average age 49 years than injured (40.1 years and involved people (40.5 years. The average ages of females killed (67.5 years, injured (43.4 years and involved (44.6 years were higher than the same values assessed for males, maybe indicating that younger females tended to be more cautious than same-age males, while older females showed an intrinsic greater vulnerability. Involved people were younger than injured people and fatalities, perhaps because younger people show greater promptness to react in dangerous situations. In the study region, floods caused more fatalities (67.9 %, injured (55 % and involved people (55.3 % than landslides. Fatalities and injuries mainly occurred outdoor, especially along roads, and the most dangerous dynamic was to be dragged by flood, causing the majority of fatalities (71.4 %. These outcomes can be used to strengthen the strategies aimed at saving people, and to customise warning campaigns according to the local risk features and people's behaviour. The results can improve the understanding of the potential impacts of geo-hydrological hazards on the population and can increase risk awareness among both administrators and citizens.

  16. Effects of damaging hydrogeological events on people throughout 15 years in a Mediterranean region

    Science.gov (United States)

    Aceto, Luigi; Aurora Pasqua, A.; Petrucci, Olga

    2017-07-01

    Damaging Hydrogeological Events (DHE) are defined as rainy periods during which landslides and floods can damage people. The paper investigated the effects of DHE on people living in Calabria (southern Italy) in the period 2000-2014, using data coming from the systematic survey of regional newspapers. Data about fatalities, people injured and people involved (not killed neither hurt) were stored in the database named PEOPLE, made of three sections: (1) event identification, (2) victim-event interaction, (3) effects on people. The outcomes highlighted vulnerability factors related to gender and age: males were killed more frequently (75 %) than females (25 %), and fatalities were older (average age 49 years) than injured (40.1 years) and involved people (40.5 years). The average ages of females killed (67.5 years), injured (43.4 years) and involved (44.6 years) were higher than the same values assessed for males, maybe indicating that younger females tended to be more cautious than same-age males, while older females showed an intrinsic greater vulnerability. Involved people were younger than injured people and fatalities, perhaps because younger people show greater promptness to react in dangerous situations. In the study region, floods caused more fatalities (67.9 %), injured (55 %) and involved people (55.3 %) than landslides. Fatalities and injuries mainly occurred outdoor, especially along roads, and the most dangerous dynamic was to be dragged by flood, causing the majority of fatalities (71.4 %). These outcomes can be used to strengthen the strategies aimed at saving people, and to customise warning campaigns according to the local risk features and people's behaviour. The results can improve the understanding of the potential impacts of geo-hydrological hazards on the population and can increase risk awareness among both administrators and citizens.

  17. Statistical evaluation of the on line core monitoring effectiveness for limiting the consequences of the fuel assembly misloading event

    International Nuclear Information System (INIS)

    Molnar, A.; Kereszturi, A.; Temesvari, E.; Korpas, L.

    2007-01-01

    In WWER-440 type reactors, on line core monitoring is used for the early indication of such abnormal events like fuel assembly misloading, inadvertent misalignment of Control Assemblies, blockage of coolant channels. The paper is focusing on the assembly misloading, which can not be indicated by other measurements. A Monte Carlo method was developed and applied to evaluate the on line core monitoring effectiveness for the indication of this abnormal event during the power increase in due time, when the consequences are still acceptable. The investigations proved the satisfactory effectiveness of the online core monitoring down to 55 % power even in case when 75 % of the temperature measurements was only available (Authors)

  18. Crop damage by primates: quantifying the key parameters of crop-raiding events.

    Directory of Open Access Journals (Sweden)

    Graham E Wallace

    Full Text Available Human-wildlife conflict often arises from crop-raiding, and insights regarding which aspects of raiding events determine crop loss are essential when developing and evaluating deterrents. However, because accounts of crop-raiding behaviour are frequently indirect, these parameters are rarely quantified or explicitly linked to crop damage. Using systematic observations of the behaviour of non-human primates on farms in western Uganda, this research identifies number of individuals raiding and duration of raid as the primary parameters determining crop loss. Secondary factors include distance travelled onto farm, age composition of the raiding group, and whether raids are in series. Regression models accounted for greater proportions of variation in crop loss when increasingly crop and species specific. Parameter values varied across primate species, probably reflecting differences in raiding tactics or perceptions of risk, and thereby providing indices of how comfortable primates are on-farm. Median raiding-group sizes were markedly smaller than the typical sizes of social groups. The research suggests that key parameters of raiding events can be used to measure the behavioural impacts of deterrents to raiding. Furthermore, farmers will benefit most from methods that discourage raiding by multiple individuals, reduce the size of raiding groups, or decrease the amount of time primates are on-farm. This study demonstrates the importance of directly relating crop loss to the parameters of raiding events, using systematic observations of the behaviour of multiple primate species.

  19. A Foreign Object Damage Event Detector Data Fusion System for Turbofan Engines

    Science.gov (United States)

    Turso, James A.; Litt, Jonathan S.

    2004-01-01

    A Data Fusion System designed to provide a reliable assessment of the occurrence of Foreign Object Damage (FOD) in a turbofan engine is presented. The FOD-event feature level fusion scheme combines knowledge of shifts in engine gas path performance obtained using a Kalman filter, with bearing accelerometer signal features extracted via wavelet analysis, to positively identify a FOD event. A fuzzy inference system provides basic probability assignments (bpa) based on features extracted from the gas path analysis and bearing accelerometers to a fusion algorithm based on the Dempster-Shafer-Yager Theory of Evidence. Details are provided on the wavelet transforms used to extract the foreign object strike features from the noisy data and on the Kalman filter-based gas path analysis. The system is demonstrated using a turbofan engine combined-effects model (CEM), providing both gas path and rotor dynamic structural response, and is suitable for rapid-prototyping of control and diagnostic systems. The fusion of the disparate data can provide significantly more reliable detection of a FOD event than the use of either method alone. The use of fuzzy inference techniques combined with Dempster-Shafer-Yager Theory of Evidence provides a theoretical justification for drawing conclusions based on imprecise or incomplete data.

  20. Crop Damage by Primates: Quantifying the Key Parameters of Crop-Raiding Events

    Science.gov (United States)

    Wallace, Graham E.; Hill, Catherine M.

    2012-01-01

    Human-wildlife conflict often arises from crop-raiding, and insights regarding which aspects of raiding events determine crop loss are essential when developing and evaluating deterrents. However, because accounts of crop-raiding behaviour are frequently indirect, these parameters are rarely quantified or explicitly linked to crop damage. Using systematic observations of the behaviour of non-human primates on farms in western Uganda, this research identifies number of individuals raiding and duration of raid as the primary parameters determining crop loss. Secondary factors include distance travelled onto farm, age composition of the raiding group, and whether raids are in series. Regression models accounted for greater proportions of variation in crop loss when increasingly crop and species specific. Parameter values varied across primate species, probably reflecting differences in raiding tactics or perceptions of risk, and thereby providing indices of how comfortable primates are on-farm. Median raiding-group sizes were markedly smaller than the typical sizes of social groups. The research suggests that key parameters of raiding events can be used to measure the behavioural impacts of deterrents to raiding. Furthermore, farmers will benefit most from methods that discourage raiding by multiple individuals, reduce the size of raiding groups, or decrease the amount of time primates are on-farm. This study demonstrates the importance of directly relating crop loss to the parameters of raiding events, using systematic observations of the behaviour of multiple primate species. PMID:23056378

  1. Core discrete event simulation model for the evaluation of health care technologies in major depressive disorder.

    Science.gov (United States)

    Vataire, Anne-Lise; Aballéa, Samuel; Antonanzas, Fernando; Roijen, Leona Hakkaart-van; Lam, Raymond W; McCrone, Paul; Persson, Ulf; Toumi, Mondher

    2014-03-01

    A review of existing economic models in major depressive disorder (MDD) highlighted the need for models with longer time horizons that also account for heterogeneity in treatment pathways between patients. A core discrete event simulation model was developed to estimate health and cost outcomes associated with alternative treatment strategies. This model simulated short- and long-term clinical events (partial response, remission, relapse, recovery, and recurrence), adverse events, and treatment changes (titration, switch, addition, and discontinuation) over up to 5 years. Several treatment pathways were defined on the basis of fictitious antidepressants with three levels of efficacy, tolerability, and price (low, medium, and high) from first line to third line. The model was populated with input data from the literature for the UK setting. Model outputs include time in different health states, quality-adjusted life-years (QALYs), and costs from National Health Service and societal perspectives. The codes are open source. Predicted costs and QALYs from this model are within the range of results from previous economic evaluations. The largest cost components from the payer perspective were physician visits and hospitalizations. Key parameters driving the predicted costs and QALYs were utility values, effectiveness, and frequency of physician visits. Differences in QALYs and costs between two strategies with different effectiveness increased approximately twofold when the time horizon increased from 1 to 5 years. The discrete event simulation model can provide a more comprehensive evaluation of different therapeutic options in MDD, compared with existing Markov models, and can be used to compare a wide range of health care technologies in various groups of patients with MDD. Copyright © 2014 International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc. All rights reserved.

  2. Precursors to potential severe core damage accidents: 1992, a status report

    International Nuclear Information System (INIS)

    1993-12-01

    This document is part of a report which documents 1992 operational events selected as accident sequence precursors. This report describes the 27 precursors identified from the 1992 licensee event reports. It also describe containment-related events; open-quote interesting close-quote events; potentially significant events that were considered impractical to analyze; copies of the licensee event reports which were cited in the cases above; and comments from the licensee and NRC in response to the preliminary reports

  3. Analysis of core-concrete interaction event with flooding for the Advanced Neutron Source reactor

    International Nuclear Information System (INIS)

    Kim, S.H.; Taleyarkhan, R.P.; Georgevich, V.; Navarro-Valenti, S.

    1993-01-01

    This paper discusses salient aspects of the methodology, assumptions, and modeling of various features related to estimation of source terms from an accident involving a molten core-concrete interaction event (with and without flooding) in the Advanced Neutron Source (ANS) reactor at the Oak Ridge National Laboratory. Various containment configurations are considered for this postulated severe accident. Several design features (such as rupture disks) are examined to study containment response during this severe accident. Also, thermal-hydraulic response of the containment and radionuclide transport and retention in the containment are studied. The results are described as transient variations of source terms, which are then used for studying off-site radiological consequences and health effects for the support of the Conceptual Safety Analysis Report for ANS. The results are also to be used to examine the effectiveness of subpile room flooding during this type of severe accident

  4. TRANSENERGY S: computer codes for coolant temperature prediction in LMFBR cores during transient events

    International Nuclear Information System (INIS)

    Glazer, S.; Todreas, N.; Rohsenow, W.; Sonin, A.

    1981-02-01

    This document is intended as a user/programmer manual for the TRANSENERGY-S computer code. The code represents an extension of the steady state ENERGY model, originally developed by E. Khan, to predict coolant and fuel pin temperatures in a single LMFBR core assembly during transient events. Effects which may be modelled in the analysis include temporal variation in gamma heating in the coolant and duct wall, rod power production, coolant inlet temperature, coolant flow rate, and thermal boundary conditions around the single assembly. Numerical formulations of energy equations in the fuel and coolant are presented, and the solution schemes and stability criteria are discussed. A detailed description of the input deck preparation is presented, as well as code logic flowcharts, and a complete program listing. TRANSENERGY-S code predictions are compared with those of two different versions of COBRA, and partial results of a 61 pin bundle test case are presented

  5. A Mediterranean nocturnal heavy rainfall and tornadic event. Part I: Overview, damage survey and radar analysis

    Science.gov (United States)

    Bech, Joan; Pineda, Nicolau; Rigo, Tomeu; Aran, Montserrat; Amaro, Jéssica; Gayà, Miquel; Arús, Joan; Montanyà, Joan; der Velde, Oscar van

    2011-06-01

    This study presents an analysis of a severe weather case that took place during the early morning of the 2nd of November 2008, when intense convective activity associated with a rapidly evolving low pressure system affected the southern coast of Catalonia (NE Spain). The synoptic framework was dominated by an upper level trough and an associated cold front extending from Gibraltar along the Mediterranean coast of the Iberian Peninsula to SE France, which moved north-eastward. South easterly winds in the north of the Balearic Islands and the coast of Catalonia favoured high values of 0-3 km storm relative helicity which combined with moderate MLCAPE values and high shear favoured the conditions for organized convection. A number of multicell storms and others exhibiting supercell features, as indicated by Doppler radar observations, clustered later in a mesoscale convective system, and moved north-eastwards across Catalonia. They produced ground-level strong damaging wind gusts, an F2 tornado, hail and heavy rainfall. Total lightning activity (intra-cloud and cloud to ground flashes) was also relevant, exhibiting several classical features such as a sudden increased rate before ground level severe damage, as discussed in a companion study. Remarkable surface observations of this event include 24 h precipitation accumulations exceeding 100 mm in four different observatories and 30 minute rainfall amounts up to 40 mm which caused local flash floods. As the convective system evolved northward later that day it also affected SE France causing large hail, ground level damaging wind gusts and heavy rainfall.

  6. Core damage vulnerability due to the loss of ESW [essential service water] systems at multiplant sites: An assessment and options

    International Nuclear Information System (INIS)

    Kohut, P.; Musicki, Z.; Fitzpatrick, R.

    1989-01-01

    The main objective of this study is to establish the core damage vulnerability caused by the failure of the ESW systems in multiplant units that have only two sw pumps per unit with crosstie capability. Design and operating data have been surveyed to derive system failure frequency. A core damage model is constructed including operating configurations, specific recovery actions, and time and leak rate dependent RCP seal LOCA model. The estimated CDF SW = 2.55 x 10 -4 /yr is significant indicating the potential vulnerability of this particular SW design arrangement. A number of different potential improvements have been considered. The addition of a swing pump serving both units is shown to have the most significant CDF reduction potential (∼50%) combined with advantageous cost/benefit aspects. 2 refs., 2 tabs

  7. Review of the SCDAP/RELAP5/MOD3.1 code structure and core T/H model before core damage

    International Nuclear Information System (INIS)

    Kim, See Darl; Kim, Dong Ha

    1998-04-01

    The SCDAP/RELAP5 code has been developed for best estimate transient simulation of light water reactor coolant systems during a severe accident. The code is being developed at the INEL under the primary sponsorship of the Office of Nuclear Regulatory Research of the U.S. NRC. As The current time, the SCDAP/RELAP5/MOD3.1 code is the result of merging the RELAP5/MOD3 and SCDAP models. The code models the coupled behavior of the reactor coolant system, core, fission product released during a severe accident transient as well as large and small break loss of coolant accidents, operational transients such as anticipated transient without SCRAM, loss of offsite power, loss of feedwater, and loss of flow. Major purpose of the report is to provide information about the characteristics of SCDAP/RELAP5/MOD3.1 core T/H models for an integrated severe accident computer code being developed under the mid/long-term project. This report analyzes the overall code structure which consists of the input processor, transient controller, and plot file handler. The basic governing equations to simulate the thermohydraulics of the primary system are also described. As the focus is currently concentrated in the core, core nodalization parameters of the intact geometry and the phenomenological subroutines for the damaged core are summarized for the future usage. In addition, the numerical approach for the heat conduction model is investigated along with heat convection model. These studies could provide a foundation for input preparation and model improvement. (author). 6 refs., 3 tabs., 4 figs

  8. Geometry of the Nojima fault at Nojima-Hirabayashi, Japan - I. A simple damage structure inferred from borehole core permeability

    Science.gov (United States)

    Lockner, David A.; Tanaka, Hidemi; Ito, Hisao; Ikeda, Ryuji; Omura, Kentaro; Naka, Hisanobu

    2009-01-01

    The 1995 Kobe (Hyogo-ken Nanbu) earthquake, M = 7.2, ruptured the Nojima fault in southwest Japan. We have studied core samples taken from two scientific drillholes that crossed the fault zone SW of the epicentral region on Awaji Island. The shallower hole, drilled by the Geological Survey of Japan (GSJ), was started 75 m to the SE of the surface trace of the Nojima fault and crossed the fault at a depth of 624 m. A deeper hole, drilled by the National Research Institute for Earth Science and Disaster Prevention (NIED) was started 302 m to the SE of the fault and crossed fault strands below a depth of 1140 m. We have measured strength and matrix permeability of core samples taken from these two drillholes. We find a strong correlation between permeability and proximity to the fault zone shear axes. The half-width of the high permeability zone (approximately 15 to 25 m) is in good agreement with the fault zone width inferred from trapped seismic wave analysis and other evidence. The fault zone core or shear axis contains clays with permeabilities of approximately 0.1 to 1 microdarcy at 50 MPa effective confining pressure (10 to 30 microdarcy at in situ pressures). Within a few meters of the fault zone core, the rock is highly fractured but has sustained little net shear. Matrix permeability of this zone is approximately 30 to 60 microdarcy at 50 MPa effective confining pressure (300 to 1000 microdarcy at in situ pressures). Outside this damage zone, matrix permeability drops below 0.01 microdarcy. The clay-rich core material has the lowest strength with a coefficient of friction of approximately 0.55. Shear strength increases with distance from the shear axis. These permeability and strength observations reveal a simple fault zone structure with a relatively weak fine-grained core surrounded by a damage zone of fractured rock. In this case, the damage zone will act as a high-permeability conduit for vertical and horizontal flow in the plane of the

  9. The Vulnerability of People to Damaging Hydrogeological Events in the Calabria Region (Southern Italy

    Directory of Open Access Journals (Sweden)

    Olga Petrucci

    2017-12-01

    Full Text Available Background: Damaging Hydrogeological Events (DHEs are severe weather periods during which floods, landslides, lightning, windstorms, hail or storm surges can harm people. Climate change is expected to increase the frequency/intensity of DHEs and, consequently, the potential harm to people. Method: We investigated the impacts of DHEs on people in Calabria (Italy over 37 years (1980–2016. Data on 7288 people physically affected by DHEs were gathered from the systematic analysis of regional newspapers and collected in the database named PEOPLE. The damage was codified in three severity levels as follows: fatalities (people who were killed, injured (people who suffered physical harm and involved (people who were present at the place where an accident occurred but survived and were not harmed. During the study period, we recorded 68 fatalities, 566 injured and 6654 people involved in the events. Results: Males were more frequently killed, injured and involved than females, and females who suffered fatalities were older than males who suffered fatalities, perhaps indicating that younger females tended to be more cautious than same-aged males, while older females showed an intrinsic greater vulnerability. Involved people were younger than injured people and fatalities, suggesting that younger people show greater promptness in reacting to dangerous situations. Floods caused the majority of the fatalities, injured and involved people, followed by landslides. Lightning was the most dangerous phenomenon, and it affected a relatively low number of people, killing 11.63% of them and causing injuries to 37.2%. Fatalities and injuries mainly occurred outdoors, largely along roads. In contrast, people indoors, essentially in public or private buildings, were more frequently involved without suffering harm. Being “dragged by water/mud” and “surrounded by water/mud”, respectively, represented the two extremes of dynamic dangerousness. The dragging

  10. Two damaging hydrogeological events in Calabria, September 2000 and November 2015. Comparative analysis of causes and effects

    Science.gov (United States)

    Petrucci, Olga; Caloiero, Tommaso; Aurora Pasqua, Angela

    2016-04-01

    Each year, especially during winter season, some episode of intense rain affects Calabria, the southernmost Italian peninsular region, triggering flash floods and mass movements that cause damage and fatalities. This work presents a comparative analysis between two events that affected the southeast sector of the region, in 2000 and 2014, respectively. The event occurred between 9th and 10th of September 2000 is known in Italy as Soverato event, after the name of the municipality where it reached the highest damage severity. In the Soverato area, more than 200 mm of rain that fell in 24 hours caused a disastrous flood that swept away a campsite at about 4 a.m., killing 13 people and hurting 45. Besides, the rain affected a larger area, causing damage in 89 (out of 409) municipalities of the region. Flooding was the most common process, which damaged housing and trading. Landslide mostly affected the road network, housing and cultivations. The most recent event affected the same regional sector between 30th October and 2nd November 2015. The daily rain recorded at some of the rain gauges of the area almost reached 400 mm. Out of the 409 municipalities of Calabria, 109 suffered damage. The most frequent types of processes were both flash floods and landslides. The most heavily damaged element was the road network: the representative picture of the event is a railway bridge destroyed by the river flow. Housing was damaged too, and 486 people were temporarily evacuated from home. The event also caused a victim killed by a flood. The event-centred study approach aims to highlight differences and similarities in both the causes and the effects of the two events that occurred at a temporal distance of 14 years. The comparative analysis focus on three main aspects: the intensity of triggering rain, the modifications of urbanised areas, and the evolution of emergency management. The comparative analysis of rain is made by comparing the return period of both daily and

  11. Survival of extensively damaged endodontically treated incisors restored with different types of posts-and-core foundation restoration material.

    Science.gov (United States)

    Lazari, Priscilla Cardoso; de Carvalho, Marco Aurélio; Del Bel Cury, Altair A; Magne, Pascal

    2018-05-01

    Which post-and-core combination will best improve the performance of extensively damaged endodontically treated incisors without a ferrule is still unclear. The purpose of this in vitro study was to investigate the restoration of extensively damaged endodontically treated incisors without a ferrule using glass-ceramic crowns bonded to various composite resin foundation restorations and 2 types of posts. Sixty decoronated endodontically treated bovine incisors without a ferrule were divided into 4 groups and restored with various post-and-core foundation restorations. NfPfB=no-ferrule (Nf) with glass-fiber post (Pf) and bulk-fill resin foundation restoration (B); NfPfP=no-ferrule (Nf) with glass-fiber post (Pf) and dual-polymerized composite resin core foundation restoration (P); NfPt=no-ferrule (Nf) with titanium post (Pt) and resin core foundation restoration; and NfPtB=no-ferrule (Nf) with titanium post (Pt) and bulk-fill resin core foundation restoration (B). Two additional groups from previously published data from the same authors (FPf=2mm of ferrule (F) and glass-fiber post (Pf) and composite resin core foundation restoration; and NfPf=no-ferrule (Nf) with glass-fiber post (Pf) and composite resin core foundation restoration), which were tested concomitantly and using the same experimental arrangement, were included for comparison. All teeth were prepared to receive bonded glass-ceramic crowns luted with dual-polymerized resin cement and were subjected to accelerated fatigue testing under submerged conditions at room temperature. Cyclic isometric loading was applied to the incisal edge at an angle of 30 degrees with a frequency of 5 Hz, beginning with a load of 100 N (5000 cycles). A 100-N load increase was applied every 15000 cycles. The specimens were loaded until failure or to a maximum of 1000 N (140000 cycles). The 6 groups (4 groups from the present study and 2 groups from the previously published study) were compared using the Kaplan-Meier survival

  12. Integrated TRAC/MELPROG analysis of core damage from a severe feedwater transient in the Oconee-1 PWR

    International Nuclear Information System (INIS)

    Henninger, R.J.; Boyack, B.E.

    1986-01-01

    A postulated complete loss-of-feedwater event in the Oconee-1 pressurized water reactor has been analyzed. With an initial version of the lonked TRAC and MELPROG codes, we have modeled the loss-of-feedwater event from initiation to the time of complete disruption of the core, which was calculated to occur by 6800 s. The highest structure temperatures otuside the vessel are on the flow path from the vessel to the pressurizer relief valve. Temperatures in excess of 1200 K could result in failure and depressurization of the primary system before vessel failure

  13. Numerical study on core damage and interpretation of in situ state of stress

    Energy Technology Data Exchange (ETDEWEB)

    Hakala, M. [Gridpoint Finland Oy (Finland)

    1999-06-01

    Core disking is a phenomenon where a diamond cored core sample will be sliced when released from a stressed host rock. Ring disking is a similar phenomenon which takes place during overcoring with a pilot hole. Because of the uniform shape and spacing of disk fracturing, it has the potential to be used for estimating the in situ state of stress. If this is feasible, it could be used in high stress states where the traditional stress measuring techniques are not valid or even possible. In this work the both the core disking and ring disking phenomena were studied based on the elastic bottom hole stress application developed and a series of fracture growth stability simulations. The results-showed that both phenomena are very complicated and site specific, but the spacing, shape, extent and initiation point are clearly stress state dependent. Throughout the work, guidelines for the in situ stress field interpretation method were developed and implemented for the borehole aligned orthogonal stress field and Poisson`s ratio of 0.25. Based on this study, the in situ state of stress can be estimated with acceptable accuracy if information on both core disking and ring disking is available. On the other hand, as an indirect method, there are no reasons to use it if direct measurements can be used. (orig.) 35 refs.

  14. Numerical study on core damage and interpretation of in situ state of stress

    International Nuclear Information System (INIS)

    Hakala, M.

    1999-06-01

    Core disking is a phenomenon where a diamond cored core sample will be sliced when released from a stressed host rock. Ring disking is a similar phenomenon which takes place during overcoring with a pilot hole. Because of the uniform shape and spacing of disk fracturing, it has the potential to be used for estimating the in situ state of stress. If this is feasible, it could be used in high stress states where the traditional stress measuring techniques are not valid or even possible. In this work the both the core disking and ring disking phenomena were studied based on the elastic bottom hole stress application developed and a series of fracture growth stability simulations. The results-showed that both phenomena are very complicated and site specific, but the spacing, shape, extent and initiation point are clearly stress state dependent. Throughout the work, guidelines for the in situ stress field interpretation method were developed and implemented for the borehole aligned orthogonal stress field and Poisson's ratio of 0.25. Based on this study, the in situ state of stress can be estimated with acceptable accuracy if information on both core disking and ring disking is available. On the other hand, as an indirect method, there are no reasons to use it if direct measurements can be used. (orig.)

  15. Effect of steam corrosion on HTGR core support post strength loss. Part II. Consequences of steam generator tube rupture event

    International Nuclear Information System (INIS)

    Wichner, R.P.

    1977-01-01

    To perform the assessment, a series of eight tube-rupture events of varying severity and probability were postulated. Case 1 pertains to the situation where the moisture detection, loop isolation, and dump procedures function as planned; the remaining seven cases suppose various defects in the moisture detection system, the core auxiliary coolant system, and the integrity of the prestressed concrete reactor vessel. Core post burnoffs beneath three typical fuel zones were estimated for each postulated event from the determined impurity compositions and core post temperature history. Two separate corrosion rate expressions were assumed, as deemed most appropriate of those published for the high-oxidant level typical in tube rupture events. It was found that the nominal core post beneath the highest power factor fuel zone would lose from 0.02 to 2.5 percent of their strength, depending on an assumed corrosion rate equation and the severity of the event. The effect of hot streaking during cooldown was determined by using preliminary estimates of its magnitude. It was found that localized strength loss beneath the highest power factor zone ranges from 0.23 to 12 percent, assuming reasonably probable hot-streaking circumstances. The combined worst case, hot streaking typical for a load-following transient and most severe accident sequence, yields an estimated strength loss of from 25 to 33 percent for localized regions beneath the highest power factor zones

  16. Core damage frequency prespectives for BWR 3/4 and Westinghouse 4-loop plants based on IPE results

    International Nuclear Information System (INIS)

    Dingman, S.; Camp, S.; LaChance, J.; Mary Drouin

    1995-01-01

    This paper discusses the core damage frequency (CDF) insights gained by analyzing the results of the Individual Plant Examinations (IPES) for two groups of plants: boiling water reactor (BWR) 3/4 plants with Reactor Core Isolation Cooling systems, and Westinghouse 4-loop plants. Wide variability was observed for the plant CDFs and for the CDFs of the contributing accident classes. On average, transients-with loss of injection, station blackout sequences, and transients with loss of decay heat removal are important contributors for the BWR 3/4 plants, while transients, station blackout sequences, and loss-of-coolant accidents are important for the Westinghouse 4-loop plants. The key factors that contribute to the variability in the results are discussed. The results are often driven by plant-specific design and operational characteristics, but differences in modeling approaches are also important for some accident classes

  17. Assessment of damage potential to the TMI-2 lower head due to thermal attack by core debris

    International Nuclear Information System (INIS)

    Cronenberg, A.W.; Behling, S.R.; Broughton, J.M.

    1986-06-01

    Camera inspection of the Three Mile Island Unit 2 (TMI-2) inlet plenum region has shown that approximately 10 to 20 percent of the core material loading may have relocated to the lower plenum. Although vessel integrity was maintained, a question of primary concern is ''how close to vessel failure'' did this accident come. This report summarizes the results of thermal analyses aimed at assessing damage potential to the TMI-2 lower head and attached instrument penetration tubes due to thermal attack by hot core debris. Results indicate that the instrument penetration nozzles could have experienced melt failure at localized hot spot regions, with attendant debris drainage and plugging of the instrument lead tubes. However, only minor direct thermal attack of the vessel liner is predicted

  18. Evaluation of re-criticality potential in Fukushima Dai-ichi reactors following core damage accidents

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-08-15

    The re-criticality potential of the debris-bed, formed of the degraded core materials, cannot be ruled out during the cooling-down procedure of the Fukushima Dai-ichi NPPs. In this study the re-criticality potential has systematically investigated based on the core disruption phase analysis using a IMPACT-SAMPSON code prepared by The Institute of Applied Energy (IAE). The results obtained for the re-criticality potential, characterized by the eigen-values k-eff dependent on the debris composition formed at the core, RPV bottom, and PCV pedestal, are reflected to the arguments on the re-criticality prevention measures, such as timing and concentration of boron-compounds, during the cooling-down process of the Fukushima Dai-ichi NPPs. (author)

  19. Interpretation of the Haestholmen in situ state of stress based on core damage observations

    International Nuclear Information System (INIS)

    Hakala, M.

    2000-01-01

    At the Haestholmen investigation site, direct in situ stress measurements, overcoring and hydraulic fracturing have been unsuccessful because of ring disking and horizontal hydraulic fracturing. Prior to this study, a detailed study on both core disking and ring disking was made, and based on those results an in situ state of stress interpretation method was developed. In this work this method is applied to the Haestholmen site. The interpretation is based on disk fracture type, spacing and shape. Also, the Hoek-Brown strength envelope and Poisson's ratio of intact rock are needed. The interpretation result is most reliable if both core disking and ring disking information at the same depth levels is available. A detailed core logging showed that ring disking is systematic below the -365 m level in the vertical overcoring stress measurement hole, HH-KR6. On the other hand, no representative core disking exists except for two points in two differently oriented subvertical boreholes HH-KR2 and HHKR7. Because the interpretation has to be based on ring disking only, upper and lower estimates for the vertical stress were set. These were gravitational and 67% of gravitational. Furthermore, the in situ stress state was assumed to be in horizontal and vertical planes, because the disking in vertical borehole HH-KR6 was not inclined. The interpretation resulted in a good estimate for the major horizontal stress but none of the horizontal stress rations ( 0.25, 0.5, 0.75 and 1.0 ) or vertical stress assumptions studied are clearly more probable the others. At the 500 m level the resulting maximum horizontal stress is 41 MPa. If a linear fit through the zero depth and zero stress point is applied, the maximum horizontal stress gradient is 0.0818 z MPa/m with a standard deviation between 5 and 12 per cent. The orientation of the major horizontal stress is 108 with standard deviation of 21 degrees. The interpreted major horizontal stress state also indicated that systematic

  20. Scale interactions in economics: application to the evaluation of the economic damages of climatic change and of extreme events

    International Nuclear Information System (INIS)

    Hallegatte, S.

    2005-06-01

    Growth models, which neglect economic disequilibria, considered as temporary, are in general used to evaluate the damaging effects generated by climatic change. This work shows, through a series of modeling experiences, the importance of disequilibria and of endogenous variability of economy in the evaluation of damages due to extreme events and climatic change. It demonstrates the impossibility to separate the evaluation of damages from the representation of growth and of economic dynamics: the comfort losses will depend on both the nature and intensity of impacts and on the dynamics and situation of the economy to which they will apply. Thus, the uncertainties about the damaging effects of future climatic changes come from both scientific uncertainties and from uncertainties about the future organization of our economies. (J.S.)

  1. Compendium of Single Event Effects, Total Ionizing Dose, and Displacement Damage for Candidate Spacecraft Electronics for NASA

    Science.gov (United States)

    LaBel, Kenneth A.; OBryan, Martha V.; Chen, Dakai; Campola, Michael J.; Casey, Megan C.; Pellish, Jonathan A.; Lauenstein, Jean-Marie; Wilcox, Edward P.; Topper, Alyson D.; Ladbury, Raymond L.; hide

    2014-01-01

    We present results and analysis investigating the effects of radiation on a variety of candidate spacecraft electronics to proton and heavy ion induced single event effects (SEE), proton-induced displacement damage (DD), and total ionizing dose (TID). Introduction: This paper is a summary of test results.NASA spacecraft are subjected to a harsh space environment that includes exposure to various types of ionizing radiation. The performance of electronic devices in a space radiation environment is often limited by its susceptibility to single event effects (SEE), total ionizing dose (TID), and displacement damage (DD). Ground-based testing is used to evaluate candidate spacecraft electronics to determine risk to spaceflight applications. Interpreting the results of radiation testing of complex devices is quite difficult. Given the rapidly changing nature of technology, radiation test data are most often application-specific and adequate understanding of the test conditions is critical. Studies discussed herein were undertaken to establish the application-specific sensitivities of candidate spacecraft and emerging electronic devices to single-event upset (SEU), single-event latchup (SEL), single-event gate rupture (SEGR), single-event burnout (SEB), single-event transient (SET), TID, enhanced low dose rate sensitivity (ELDRS), and DD effects.

  2. Radiation damage studies on new liquid scintillators and liquid-core scintillating fibers

    International Nuclear Information System (INIS)

    Golovkin, S.V.

    1994-01-01

    The radiation resistant of some new liquid scintillation and capillaries filled with liquid scintillators has been presented. It was found that scintillation efficiency of the scintillator based on 1-methyl naphthalene with a new R39 only by 10% at the dose of 190 Mrad and the radiation resistance of thin liquid-core scintillating was decreased fibers exceeded 60 Mrad. 35 refs

  3. Different timing features in brain processing of core and moral disgust pictures: an event-related potentials study.

    Directory of Open Access Journals (Sweden)

    Xiangyi Zhang

    Full Text Available Disgust, an emotion motivating withdrawal from offensive stimuli, protects us from the risk of biological pathogens and sociomoral violations. Homogeneity of its two types, namely, core and moral disgust has been under intensive debate. To examine the dynamic relationship between them, we recorded event-related potentials (ERPs for core disgust, moral disgust and neutral pictures while participants performed a modified oddball task. ERP analysis revealed that N1 and P2 amplitudes were largest for the core disgust pictures, indicating automatic processing of the core disgust-evoking pictures. N2 amplitudes were higher for pictures evoking moral disgust relative to core disgust and neutral pictures, reflecting a violation of social norms. The core disgust pictures elicited larger P3 and late positive potential (LPP amplitudes in comparison with the moral disgust pictures which, in turn, elicited larger P3 and LPP amplitudes when compared to the neutral pictures. Taken together, these findings indicated that core and moral disgust pictures elicited different neural activities at various stages of information processing, which provided supporting evidence for the heterogeneity of disgust.

  4. Different timing features in brain processing of core and moral disgust pictures: an event-related potentials study.

    Science.gov (United States)

    Zhang, Xiangyi; Guo, Qi; Zhang, Youxue; Lou, Liandi; Ding, Daoqun

    2015-01-01

    Disgust, an emotion motivating withdrawal from offensive stimuli, protects us from the risk of biological pathogens and sociomoral violations. Homogeneity of its two types, namely, core and moral disgust has been under intensive debate. To examine the dynamic relationship between them, we recorded event-related potentials (ERPs) for core disgust, moral disgust and neutral pictures while participants performed a modified oddball task. ERP analysis revealed that N1 and P2 amplitudes were largest for the core disgust pictures, indicating automatic processing of the core disgust-evoking pictures. N2 amplitudes were higher for pictures evoking moral disgust relative to core disgust and neutral pictures, reflecting a violation of social norms. The core disgust pictures elicited larger P3 and late positive potential (LPP) amplitudes in comparison with the moral disgust pictures which, in turn, elicited larger P3 and LPP amplitudes when compared to the neutral pictures. Taken together, these findings indicated that core and moral disgust pictures elicited different neural activities at various stages of information processing, which provided supporting evidence for the heterogeneity of disgust.

  5. Two Extreme Climate Events of the Last 1000 Years Recorded in Himalayan and Andean Ice Cores: Impacts on Humans

    Science.gov (United States)

    Thompson, L. G.; Mosley-Thompson, E. S.; Davis, M. E.; Kenny, D. V.; Lin, P.

    2013-12-01

    In the last few decades numerous studies have linked pandemic influenza, cholera, malaria, and viral pneumonia, as well as droughts, famines and global crises, to the El Niño-Southern Oscillation (ENSO). Two annually resolved ice core records, one from Dasuopu Glacier in the Himalaya and one from the Quelccaya Ice Cap in the tropical Peruvian Andes provide an opportunity to investigate these relationships on opposite sides of the Pacific Basin for the last 1000 years. The Dasuopu record provides an annual history from 1440 to 1997 CE and a decadally resolved record from 1000 to 1440 CE while the Quelccaya ice core provides annual resolution over the last 1000 years. Major ENSO events are often recorded in the oxygen isotope, insoluble dust, and chemical records from these cores. Here we investigate outbreaks of diseases, famines and global crises during two of the largest events recorded in the chemistry of these cores, particularly large peaks in the concentrations of chloride (Cl-) and fluoride (Fl-). One event is centered on 1789 to 1800 CE and the second begins abruptly in 1345 and tapers off after 1360 CE. These Cl- and F- peaks represent major droughts and reflect the abundance of continental atmospheric dust, derived in part from dried lake beds in drought stricken regions upwind of the core sites. For Dasuopu the likely sources are in India while for Quelccaya the sources would be the Andean Altiplano. Both regions are subject to drought conditions during the El Niño phase of the ENSO cycle. These two events persist longer (10 to 15 years) than today's typical ENSO events in the Pacific Ocean Basin. The 1789 to 1800 CE event was associated with a very strong El Niño event and was coincidental with the Boji Bara famine resulting from extended droughts that led to over 600,000 deaths in central India by 1792. Similarly extensive droughts are documented in Central and South America. Likewise, the 1345 to 1360 CE event, although poorly documented

  6. Concept and methodology for evaluating core damage frequency considering failure correlation at multi units and sites and its application

    Energy Technology Data Exchange (ETDEWEB)

    Ebisawa, K.; Teragaki, T.; Nomura, S. [Former Incorporated Administrative Agency, Japan Nuclear Safety Organization (Japan); Abe, H., E-mail: Hiroshi_abe@nsr.go.jp [Former Incorporated Administrative Agency, Japan Nuclear Safety Organization (Japan); Shigemori, M.; Shimomoto, M. [Mizuho Information & Research Institute, 2-3, Kanda-Nishikicho, Chiyoda-ku, Tokyo (Japan)

    2015-07-15

    Highlights: • We develop a method to evaluate CDF considering failure correlation at multi units. • We develop a procedure to evaluate correlation coefficient between multi components. • We evaluate CDF at two different BWR units using correlation coefficients. • We confirm the validity of method and correlation coefficient through the evaluation. - Abstract: The Tohoku earthquake (Mw9.0) occurred on March 11, 2011 and caused a large tsunami. The Fukushima Daiichi Nuclear Power Plant with six units were overwhelmed by the tsunami and core damage occurred. Authors proposed the concept and method for evaluating core damage frequency (CDF) considering failure correlation at the multi units and sites. Based on the above method, one of authors developed the procedure for evaluating the failure correlation coefficient and response correlation coefficient between the multi components under the strong seismic motion. These method and failure correlation coefficients were applied to two different BWR units and their CDF was evaluated by seismic probabilistic risk assessment technology. Through this quantitative evaluation, the validity of the method and failure correlation coefficient was confirmed.

  7. Concept and methodology for evaluating core damage frequency considering failure correlation at multi units and sites and its application

    International Nuclear Information System (INIS)

    Ebisawa, K.; Teragaki, T.; Nomura, S.; Abe, H.; Shigemori, M.; Shimomoto, M.

    2015-01-01

    Highlights: • We develop a method to evaluate CDF considering failure correlation at multi units. • We develop a procedure to evaluate correlation coefficient between multi components. • We evaluate CDF at two different BWR units using correlation coefficients. • We confirm the validity of method and correlation coefficient through the evaluation. - Abstract: The Tohoku earthquake (Mw9.0) occurred on March 11, 2011 and caused a large tsunami. The Fukushima Daiichi Nuclear Power Plant with six units were overwhelmed by the tsunami and core damage occurred. Authors proposed the concept and method for evaluating core damage frequency (CDF) considering failure correlation at the multi units and sites. Based on the above method, one of authors developed the procedure for evaluating the failure correlation coefficient and response correlation coefficient between the multi components under the strong seismic motion. These method and failure correlation coefficients were applied to two different BWR units and their CDF was evaluated by seismic probabilistic risk assessment technology. Through this quantitative evaluation, the validity of the method and failure correlation coefficient was confirmed

  8. Design criteria for a self-actuated shutdown system to ensure limitation of core damage

    International Nuclear Information System (INIS)

    Deane, N.A.; Atcheson, D.B.

    1981-09-01

    Safety-based functional requirements and design criteria for a self-actuated shutdown system (SASS) are derived in accordance with LOA-2 success criteria and reliability goals. The design basis transients have been defined and evaluated for the CDS Phase II design, which is a 2550 MWt mixed oxide heterogeneous core reactor. A partial set of reactor responses for selected transients is provided as a function of SASS characteristics such as reactivity worth, trip points, and insertion times

  9. The contribution to site core damage frequency from independent occurrences of initiators in two or more units: How low is it?

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong-San; Park, Jin Hee; Lim, Ho Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    Stutzke estimated the site risk by summing the contribution from common cause initiators and the contribution from single-unit initiators. He considered some kinds of multi-unit accident sequences caused by single-unit initiators. However, the contribution from independent occurrences of initiators in two or more units at a site was not taken into account. The purpose of this study is to estimate the contribution to site core damage frequency (CDF) from simultaneous occurrences of independent initiators in two or more units at the same site. Some assumptions and methods used in this analysis are firstly described, and the results and conclusions of the analysis are described. In this study, the contribution to site core damage frequency (CDF) from simultaneous occurrences of independent initiators in two or more units at the same site was estimated. A Korean six-unit site was selected as the reference site and the at-power internal events Level 1 PSA model for an OPR1000 unit at the reference site was used as the base model, and was modified to deal with some major dependencies between units at the site. Specifically, the availability of the AAC D/G, dependencies between offsite power recovery actions in different unis, and inter-unit CCF modeling for risk-significant components such as diesel generators were taken into account. As a result, the sum of dual-unit CDF due to independent occurrences of initiators in two units at the reference site was estimated to be sufficiently low to be neglected.

  10. Evaluation of the gravity-injection capability for core cooling after a loss-of-SDC event

    International Nuclear Information System (INIS)

    Seul, Kwang Won; Bang, Young Seok; Kim, Hho Jung

    1999-01-01

    In order to evaluate the gravity-drain capability to maintain core cooling after a loss-of-shutdown-cooling event during shutdown operation, the plant conditions of the Young Gwang Units 3 and 4 were reviewed. The six cases of possible gravity-drain paths using the water of the refueling water storage tank (RWST) were identified and the thermal hydraulic analyses were performed using RELAP5/MOD3.2 code. The core cooling capability was dependent on the gravity-drain paths and the drain rate. In the cases with the injection path and opening on the different leg side, the system was well depressurized after gravity-injection and the core boiling was successfully prevented for a long-term transient. However, in the cases with the injection path and opening on the cold leg side, the core coolant continued boiling although the system pressure remains atmospheric after gravity-injection because the cold water injected from the RWST was bypassed the core region. In the cases with the higher pressurizer opening than the RWST water level, the system was also pressurized by the water-hold in the pressurizer and the core was uncovered because the gravity-injection from the RWST stopped due to the high system pressure. In addition, from the sensitivity study on the gravity-injection flow rates, it was found that about 54 kg/s of RWST drain rate was required to maintain the core cooling. Those analysis results would provide useful information to operators coping with the event

  11. Damage Assessment and Monitoring of Cultural Heritage Places in a Disaster and Post-Disaster Event - a Case Study of Syria

    Science.gov (United States)

    Vafadari, A.; Philip, G.; Jennings, R.

    2017-08-01

    In recent decades, and in response to an increased focus on disastrous events ranging from armed conflict to natural events that impact cultural heritage, there is a need for methodologies and approaches to better manage the effects of disaster on cultural heritage. This paper presents the approaches used in the development of a Historic Environment Record (HER) for Syria. It describes the requirements and methodologies used for systematic emergency recording and assessment of cultural heritage. It also presents the type of information needed to record in the aftermath of disaster to assess the scale of damage and destruction. Started as a project at Durham University, the database is now being developed as part of the EAMENA (Endangered Archaeology in the Middle East and North Africa) project. The core dataset incorporates information and data from archaeological surveys undertaken in Syria by research projects in recent decades and began life as a development of the Shirīn initiative1. The focus of this project is to provide a tool not only for the recording and inventory of sites and monuments, but also to record damage and threats, their causes, and assess their magnitude. It will also record and measure the significance in order to be able to prioritize emergency and preservation responses. The database aims to set procedures for carrying out systematic rapid condition assessment (to record damage) and risk assessment (to record threat and level of risk) of heritage places, on the basis of both on the ground and remote assessment. Given the large number of heritage properties damaged by conflict, the implementation of rapid assessment methods to quickly identify and record level of damage and condition is essential, as it will provide the evidence to support effective prioritization of efforts and resources, and decisions on the appropriate levels of intervention and methods of treatment. The predefined data entry categories, use of a data standard, and

  12. DAMAGE ASSESSMENT AND MONITORING OF CULTURAL HERITAGE PLACES IN A DISASTER AND POST-DISASTER EVENT – A CASE STUDY OF SYRIA

    Directory of Open Access Journals (Sweden)

    A. Vafadari

    2017-08-01

    Full Text Available In recent decades, and in response to an increased focus on disastrous events ranging from armed conflict to natural events that impact cultural heritage, there is a need for methodologies and approaches to better manage the effects of disaster on cultural heritage. This paper presents the approaches used in the development of a Historic Environment Record (HER for Syria. It describes the requirements and methodologies used for systematic emergency recording and assessment of cultural heritage. It also presents the type of information needed to record in the aftermath of disaster to assess the scale of damage and destruction. Started as a project at Durham University, the database is now being developed as part of the EAMENA (Endangered Archaeology in the Middle East and North Africa project. The core dataset incorporates information and data from archaeological surveys undertaken in Syria by research projects in recent decades and began life as a development of the Shirīn initiative1. The focus of this project is to provide a tool not only for the recording and inventory of sites and monuments, but also to record damage and threats, their causes, and assess their magnitude. It will also record and measure the significance in order to be able to prioritize emergency and preservation responses. The database aims to set procedures for carrying out systematic rapid condition assessment (to record damage and risk assessment (to record threat and level of risk of heritage places, on the basis of both on the ground and remote assessment. Given the large number of heritage properties damaged by conflict, the implementation of rapid assessment methods to quickly identify and record level of damage and condition is essential, as it will provide the evidence to support effective prioritization of efforts and resources, and decisions on the appropriate levels of intervention and methods of treatment. The predefined data entry categories, use of a data

  13. Development of accident sequence precursors methodologies for core damage Probabilities in NPPs

    International Nuclear Information System (INIS)

    Munoz, R.; Minguez, E.; Melendez, E.; Sanchez-Perea, M.; Izquierdo, J.M.

    1998-01-01

    Several licensing programs have focused on the evaluation of the importance of operating events occurred in NPPs. Some have worked the dynamic aspects of the sequence of events involved, reproducing the incidents, while others are based on PSA applications to incident analysis. A method that controls the two above approaches to determine risk analysis derives from the Integrated Safety Assessment methodology (ISA). The dynamics of the event is followed by transient simulation in tree form, building a Setpoint or Deterministic Dynamic Event Tree (DDET). When a setpoint is reached, the actuation of a protection is triggered, then the tree is opened in branches corresponding to different functioning states. The engineering simulator with the new states followers each branch. One of these states is the nominal one, which is the PSA is associated to the success criterion of the system. The probability of the sequence is calculated in parallel to the dynamics. The following tools should perform the couple simulation: 1. A Scheduler that drives the simulation of the different sequences, and open branches upon demand. It will be the unique generator of processes while constructing the tree calculation, and will develop the computation in a distributed computational environment. 2. The Plant Simulator, which models the plant systems and the operator actions throughout a sequence. It receives the state of the equipment in each sequence and must provide information about setpoint crossing to the Scheduler. It will receive decision flags to continue or to stop each sequence, and to send new conditions to other plant simulators. 3. The Probability Calculator, linked only to the Scheduler, is the fault trees associated with each event tree header and performing their Boolean product. (Author)

  14. Flow with boiling in four-cusp channels simulating damaged core in PWR type reactors

    International Nuclear Information System (INIS)

    Esteves, M.M.

    1985-01-01

    The study of subcooled nucleate flow boiling in non-circular channels is of great importance to engineering applications in particular to Nuclear Engineering. In the present work, an experimental apparatus, consisting basically of a refrigeration system, running on refrigerant-12, has been developed. Preliminary tests were made with a circular tube. The main objective has been to analyse subcooled flow boiling in four-cusp channels simulating the flow conditions in a PWR core degraded by accident. Correlations were developed for the forced convection film coefficient for both single-phase and subcooled flow boiling. The incipience of boiling in such geometry has also been studied. (author) [pt

  15. First neutrino events seen by the core of the OPERA experiment (CNGS) on 2 October 2007

    CERN Multimedia

    2007-01-01

    The reconstruction of the core of a neutrino interaction at OPERA. The neutrino arriving from the left of the image has interacted with the lead of a brick, producing various particles identifiable by their tracks visible in the emulsion.

  16. Estimation of the core-wide fuel rod damage during a LWR LOCA

    International Nuclear Information System (INIS)

    Mattila, L.; Sairanen, R.; Stengaard, J.-O.

    1975-01-01

    The number of fuel rods puncturing during a LWR LOCA must be estimated as a part of the plant radioactivity release analysis. Due to the great number of fuel rods in the core and the great number of contributing parameters, many of them associated with wide uncertainty and/or truly random variability limits, probabilistic methods are well applicable. A succession of computer models developed for this purpose is described together with applications to WWER-440 PWR. Deterministic models are shown to be seriously inadequate and even misleading under certain circumstances. A simple analytical probabilistic model appears to be suitable for many applications. Monte Carlo techniques allow the development of such sophisticated models that errors in the input data presently available probably become dominant in the residual uncertainty of the corewide fuel rod puncture analysis. (author)

  17. Primary Damage Characteristics in Metals Under Irradiation in the Cores of Thermal and Fast Reactors

    International Nuclear Information System (INIS)

    Pechenkin, V.A.

    2012-01-01

    For an analysis and forecasting of radiation-induced phenomena in structural materials of WWERs, PWRs and BN reactors the fast neutron fluence is usually used (for structural materials of the reactor cores and internals the fluence of neutrons with energy > 0.1 MeV, for WWER and PWRs vessel steels the fluence of neutrons with energy > 0.5 MeV in Russia and East Europe, and with energy > 1.0 MeV in USA and France). Displacements per atom (dpa) seem to be a more appropriate correlation parameter, because it allows comparing the results of materials irradiation in different neutron energy spectra or with different types of particles (neutrons, ions, fast electrons). Energy spectra of primary knocked atoms (PKA) and 'effective' dpa, which are introduced to take into account the point defect recombination during the relaxation stage of a displacement cascade, can be still better representation of the effect of irradiation on material properties. In this work the results of calculating dose rates (dpa/s, NRT-model), PKA energy spectra and PKA mean energies in metals under irradiation in the cores of Russian reactors WWER-440, WWER-1000 (both power thermal reactors) and BN-600 (power fast reactor) and BR-10 (test fast reactor) are presented. In all the reactors Fe and Zr are considered, with addition of Ti and W in BN-600. 'Effective' dose rates in these metals are calculated. Limitations and uncertainties in the standard dpa formulation (the NRT-dpa) are discussed. IPPE activities in the fields related to the TM subject are considered

  18. Developing Daily Quantitative Damage Estimates From Geospatial Layers To Support Post Event Recovery

    Science.gov (United States)

    Woods, B. K.; Wei, L. H.; Connor, T. C.

    2014-12-01

    With the growth of natural hazard data available in near real-time it is increasingly feasible to deliver damage estimates caused by natural disasters. These estimates can be used in disaster management setting or by commercial entities to optimize the deployment of resources and/or routing of goods and materials. This work outlines an end-to-end, modular process to generate estimates of damage caused by severe weather. The processing stream consists of five generic components: 1) Hazard modules that provide quantitate data layers for each peril. 2) Standardized methods to map the hazard data to an exposure layer based on atomic geospatial blocks. 3) Peril-specific damage functions that compute damage metrics at the atomic geospatial block level. 4) Standardized data aggregators, which map damage to user-specific geometries. 5) Data dissemination modules, which provide resulting damage estimates in a variety of output forms. This presentation provides a description of this generic tool set, and an illustrated example using HWRF-based hazard data for Hurricane Arthur (2014). In this example, the Python-based real-time processing ingests GRIB2 output from the HWRF numerical model, dynamically downscales it in conjunctions with a land cover database using a multiprocessing pool, and a just-in-time compiler (JIT). The resulting wind fields are contoured, and ingested into a PostGIS database using OGR. Finally, the damage estimates are calculated at the atomic block level and aggregated to user-defined regions using PostgreSQL queries to construct application specific tabular and graphics output.

  19. Calculation of Core Damage Frequency for the Change of the Common Cause Failure Parameters According to the Testing Strategies

    International Nuclear Information System (INIS)

    Kang, Dae Il; Kim, Kil You; Jin, Young Ho; Kim, Tae Woon

    2011-01-01

    Common cause failure (CCF) probabilities are differently estimated according to testing strategies. There are two representative testing schemes; staggered testing and non-staggered testing schemes. For the cases where trains or channels of standby safety systems consisting of more than two redundant components are tested in a staggered manner, the standby safety components within a train can be tested simultaneously or consecutively. In this case, mixed testing scheme, staggered and non-staggered testing schemes, are used for testing the components. Kang et al. derived the formulas for the estimations of the CCF probabilities of the components under the mixed testing scheme. This paper presents the sensitivity study results on the core damage frequency (CDF) of the SMART (System-integrated Modular Advanced Reactor) for the changes of the CCF parameters according to the testing strategies

  20. Detection and control of potential core damage during a small-break LOCA

    International Nuclear Information System (INIS)

    Thomas, G.R.; Zebroski, E.L.

    1981-01-01

    A refreshing development in small-break LOCA analysis and testing is the recognition that this work can be of real value to a plant operator. Event-trees, or safety sequence diagrams, are being made increasingly realistic and are being used to develop and to test the abnormal transient operating guidelines (ATOGs) which provide a basis for operator response, training, and simulator work now under way. Perhaps the most monumental lesson of the TMI-2 accident is that the tradition of extreme worst-case analysis and data gathering can provide a directly negative contribution to safety if it is used as the basis for designing procedures and training of operator response. The event-trees for guiding operator response to abnormal conditions, ATOGs, must be based on physically realistic, best-estimate models. Possibly, the most dramatic risk reduction achieved will be attained through the use of realistic accident analysis, which leads to realistic operator guidelines and training, improved display of the critical information to the operator, and improved management structure. Given the dominant contribution of small-break LOCAs to the overall public risk envelope, realism should be the primary banner for future work in this field

  1. Damaged mitochondria in Fanconi anemia - an isolated event or a general phenomenon?

    Science.gov (United States)

    Pagano, Giovanni; Shyamsunder, Pavithra; Verma, Rama S; Lyakhovich, Alex

    2014-01-01

    Fanconi anemia (FA) is known as an inherited bone marrow failure syndrome associated with cancer predisposition and susceptibility to a number of DNA damaging stimuli, along with a number of clinical features such as upper limb malformations, increased diabetes incidence and typical anomalies in skin pigmentation. The proteins encoded by FA-defective genes (FANC proteins) display well-established roles in DNA damage and repair pathways. Moreover, some independent studies have revealed that mitochondrial dysfunction (MDF) is also involved in FA phenotype. Unconfined to FA, we have shown that other syndromes featuring DNA damage and repair (such as ataxia-telangiectasia, AT, and Werner syndrome, WS) display MDF-related phenotypes, along with oxidative stress (OS) that, altogether, may play major roles in these diseases. Experimental and clinical studies are warranted in the prospect of future therapies to be focused on compounds scavenging reactive oxygen species (ROS) as well as protecting mitochondrial functions.

  2. Gene conversion and reversion events in Saccharomyces cerevisiae. Model for study of gamma radiation damage

    International Nuclear Information System (INIS)

    Moreno, Damaris; Fuentes, Jorge L.; Prieto Miranda, Enrique F.; Sanchez Lamar, Angel; Baluja, Ligia

    2004-01-01

    Radiosensitivity and kinetics of induction of gene conversion and reversion events in Saccharomyces cerevisiae strain D7 to gamma radiation at dose ranges from 100 to 800 Gy and 50 to 300 Gy respectively were studied. A source of 60Co PX- -30 at a dose rate of 49,43 GY/min was utilized. The cell survival curve showed DL50 of 150 Gy. Cell death kinetics was linear and adjusted over 98 %. The induction of gene conversion events was significant in relation to control from 50 Gy on. However, gene reversion was significant only at 200 Gy. Generally speaking, gene conversion event frequencies were higher than those of reversion, which indicates that gamma radiation preferably induces recombinogenic events. Both the conversion and reversion events showed exponential dependence on gamma radiation dose. The relative benefits of this test for mutagenesis and anti-mutagenesis studies were debated in this paper

  3. 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.

  4. The loadings and strength of nuclear power plant structures in core damage accidents

    International Nuclear Information System (INIS)

    Varpasuo, P.

    1994-01-01

    The reactor cavity of VVER-91 NPP is a thick-walled, cylindrical reinforced concrete structure. In case of molten core-water reaction during the severe reactor accident the load carrying capacity of the cavity structure is of interest against the short impulse type loading caused by the steam explosion phenomenon. The assumed size of the impulse was 20 kPa-s and the duration was 10 ms. This investigation was divided in several phases. First, the elastic response of the cavity was determined using the ABAQUS code. Next, the static response of the cavity was evaluated using elasto-plastic properties of reinforcement and concrete and also taking into account the cracking of the concrete. This analysis was done with the aid of ABAQUS/STANDARD and ANSYS codes and the obtained results agreed reasonably with each other. In order to obtain a qualitative picture of the behaviour of the structure under the impulse load a simplified single degree of freedorn model was developed. The hoop reinforcement of the cavity was taken as an elasto-plastic spring and the wall concrete acted as a mass. Using this model the suitable amount of hoop reinforcement was determined. In next phase, the dynamic analysis of the structure was attempted using elasto-plastic material properties and concrete cracking. (13 refs., 57 figs.)

  5. Pedigree analyses of yeast cells recovering from DNA damage allow assignment of lethal events to individual post-treatment generations

    International Nuclear Information System (INIS)

    Klein, F.; Karwan, A.; Wintersberger, U.

    1990-01-01

    Haploid cells of Saccharomyces cerevisiae were treated with different DNA damaging agents at various doses. A study of the progeny of individual such cells allowed the assignment of lethal events to distinct post treatment generations. By microscopically inspecting those cells which were not able to form visible colonies the authors could discriminate between cells dying from immediately effective lethal hits and those generating microcolonies probably as a consequence of lethal mutation(s). The experimentally obtained numbers of lethal events were mathematically transformed into mean probabilities of lethal fixations at taking place in cells of certain post treatment generations. Such analyses give detailed insight into the kinetics of lethality as a consequence of different kinds of DNA damage. For example, X-irradiated cells lost viability mainly by lethal hits, only at a higher dose also lethal mutations fixed in the cells that were in direct contact with the mutagen, but not in later generations, occurred. Ethyl methanesulfonate (EMS)-treated cells were hit by 00-fixations in a dose dependent manner. The distribution of all sorts of lethal fixations taken together, which occurred in the EMS-damaged cell families, was not random. For comparison analyses of cells treated with methyl methanesulfonate, N-methyl-N'-nitro-N-nitrosoguanidine and nitrous acid are also reported

  6. Phenomena occuring in the reactor coolant system during severe core damage accidents

    International Nuclear Information System (INIS)

    Malinauskas, A.P.

    1990-01-01

    The reactor coolant system (RCS) of a nuclear power plant consists of the reactor pressure vessel and the piping and associated components that are required for the continuous circulation of the coolant which is used to maintain thermal equilibrium throughout the system. This paper discusses, how in the event of an accident, the RCS also serves as one of several barriers to the escape of radiotoxic material into the biosphere. The physical and chemical processes occurring within the RCS during normal operation of the reactor are relatively uncomplicated and are reasonably well understood. When the flow of coolant is properly adjusted, the thermal energy resulting from nuclear fission (or, in the shutdown mode, from radioactive decay processes) and secondary inputs, such as pumps, are exactly balanced by thermal losses through the RCS boundaries and to the various heat sinks that are employed to effect the conversion of heat to electrical energy. Because all of the heat and mass fluxes remain sensibly constant with time, mathematical descriptions of the thermophysical processes are relatively straightforward, even for boiling water reactor (BWR) systems. Although the coolant in a BWR does undergo phase changes, the phase boundaries remain well-defined and time-invariant

  7. Comparison of computer codes relative to the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

    International Nuclear Information System (INIS)

    Fermandjian, J.; Bunz, H.; Dunbar, I.; Gauvain, J.; Ricchena, R.

    1986-01-01

    The present study concerns a comparative exercise, performed within the framework of the Commission of the European Communities, of the computer codes (AEROSIM-M, UK; AEROSOLS/B1, France; CORRAL-2, CEC and NAUA Mod5, Germany) used in order to assess the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR. Topics considered in this paper include aerosols, containment buildings, reactor safety, fission product release, reactor cores, meltdown, and monitoring

  8. Non-equilibrium effects of core-cooling and time-dependent internal heating on mantle flush events

    Directory of Open Access Journals (Sweden)

    D. A. Yuen

    1995-01-01

    Full Text Available We have examined the non-equilibrium effects of core-cooling and time-dependent internal-heating on the thermal evolution of the Earth's mantle and on mantle flush events caused by the two major phase transitions. Both two- and three-dimensional models have been employed. The mantle viscosity responds to the secular cooling through changes in the averaged temperature field. A viscosity which decreases algebraically with the average temperature has been considered. The time-dependent internal-heating is prescribed to decrease exponentially with a single decay time. We have studied the thermal histories with initial Rayleigh numbers between 2 x 107 and 108 . Flush events, driven by the non-equilibrium forcings, are much more dramatic than those produced by the equilibrium boundary conditions and constant internal heating. Multiple flush events are found under non-equilibrium conditions in which there is very little internal heating or very fast decay rates of internal-heating. Otherwise, the flush events take place in a relatively continuous fashion. Prior to massive flush events small-scale percolative structures appear in the 3D temperature fields. Time-dependent signatures, such as the surface heat flux, also exhibits high frequency oscillatory patterns prior to massive flush events. These two observations suggest that the flush event may be a self-organized critical phenomenon. The Nusselt number as a function of the time-varying Ra does not follow the Nusselt vs. Rayleigh number power-law relationship based on equilibrium (constant temperature boundary conditions. Instead Nu(t may vary non-monotonically with time because of the mantle flush events. Convective processes in the mantle operate quite differently under non-equilibrium conditions from its behaviour under the usual equilibrium situations.

  9. Melt damage simulation of W-macrobrush and divertor gaps after multiple transient events in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Bazylev, B.N. [Forschungszentrum Karlsruhe, IHM, P.O. Box 3640, 76021 Karlsruhe (Germany)]. E-mail: bazylev@ihm.fzk.de; Janeschitz, G. [Forschungszentrum Karlsruhe, Fusion, P.O. Box 3640, 76021 Karlsruhe (Germany); Landman, I.S. [Forschungszentrum Karlsruhe, IHM, P.O. Box 3640, 76021 Karlsruhe (Germany); Loarte, A. [EFDA-CSU, Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany); Pestchanyi, S.E. [Forschungszentrum Karlsruhe, IHM, P.O. Box 3640, 76021 Karlsruhe (Germany)

    2007-06-15

    Tungsten in the form of macrobrush structure is foreseen as one of two candidate materials for the ITER divertor and dome. In ITER, even for moderate and weak ELMs when a thin shielding layer does not protect the armour surface from the dumped plasma, the main mechanisms of metallic target damage remain surface melting and melt motion erosion, which determines the lifetime of the plasma facing components. The melt erosion of W-macrobrush targets with different geometry of brush surface under the heat loads caused by weak ELMs is numerically investigated using the modified code MEMOS. The optimal angle of brush surface inclination that provides a minimum of surface roughness is estimated for given inclination angles of impacting plasma stream and given parameters of the macrobrush target. For multiple disruptions the damage of the dome gaps and the gaps between divertor cassettes caused by the radiation impact is estimated.

  10. Melt damage simulation of W-macrobrush and divertor gaps after multiple transient events in ITER

    Science.gov (United States)

    Bazylev, B. N.; Janeschitz, G.; Landman, I. S.; Loarte, A.; Pestchanyi, S. E.

    2007-06-01

    Tungsten in the form of macrobrush structure is foreseen as one of two candidate materials for the ITER divertor and dome. In ITER, even for moderate and weak ELMs when a thin shielding layer does not protect the armour surface from the dumped plasma, the main mechanisms of metallic target damage remain surface melting and melt motion erosion, which determines the lifetime of the plasma facing components. The melt erosion of W-macrobrush targets with different geometry of brush surface under the heat loads caused by weak ELMs is numerically investigated using the modified code MEMOS. The optimal angle of brush surface inclination that provides a minimum of surface roughness is estimated for given inclination angles of impacting plasma stream and given parameters of the macrobrush target. For multiple disruptions the damage of the dome gaps and the gaps between divertor cassettes caused by the radiation impact is estimated.

  11. Melt damage simulation of W-macrobrush and divertor gaps after multiple transient events in ITER

    International Nuclear Information System (INIS)

    Bazylev, B.N.; Janeschitz, G.; Landman, I.S.; Loarte, A.; Pestchanyi, S.E.

    2007-01-01

    Tungsten in the form of macrobrush structure is foreseen as one of two candidate materials for the ITER divertor and dome. In ITER, even for moderate and weak ELMs when a thin shielding layer does not protect the armour surface from the dumped plasma, the main mechanisms of metallic target damage remain surface melting and melt motion erosion, which determines the lifetime of the plasma facing components. The melt erosion of W-macrobrush targets with different geometry of brush surface under the heat loads caused by weak ELMs is numerically investigated using the modified code MEMOS. The optimal angle of brush surface inclination that provides a minimum of surface roughness is estimated for given inclination angles of impacting plasma stream and given parameters of the macrobrush target. For multiple disruptions the damage of the dome gaps and the gaps between divertor cassettes caused by the radiation impact is estimated

  12. Determinants of property damage recovery time amongst households affected by an extreme flood event in Metro Manila, Philippines

    Directory of Open Access Journals (Sweden)

    Jamil Paolo Francisco

    2014-08-01

    Full Text Available This study identified the factors that influence household recovery following an extreme flood event, measured in terms of the length of time to repair, rebuild or replace damaged private property. Data was obtained through a survey of 400 households in Marikina City in Metro Manila, Philippines. Results from the empirical analysis indicated that household income, access to credit (borrowing, the use of a flood alarm system, access to safe shelter, membership in a community organisation, adoption of disaster-specific anticipatory measures and adoption of general preventive measures significantly reduced the time it took for affected households to recover from property damage. Evacuation, relief aid, type of housing, education, household size and frequency of flooding in the area did not have significant effects.

  13. BWR [boiling water reactor] core criticality versus water level during an ATWS [anticipated transient without scram] event

    International Nuclear Information System (INIS)

    Sehgal, B.R.; Peng, C.M.; Maly, J.

    1988-01-01

    The BWR [boiling water reactor] emergency procedures guidelines recommend management of core water level to reduce the power generated during an anticipated transient without scram (ATWS) event. BWR power level variation has traditionally been calculated in the system codes using a 1-D [one-dimensional] 2-group neutron kinetics model to determine criticality. This methodology used also for calculating criticality of the partially covered BWR cores has, however, never been validated against data. In this paper, the power level versus water level issues in an ATWS severe accident are introduced and the accuracy of the traditional methodology is investigated by comparing with measured data. It is found that the 1-D 2-group treatment is not adequate for accurate predictions of criticality and therefore the system power level for the water level variations that may be encountered in a prototypical ATWS severe accident. It is believed that the current predictions for power level may be too high

  14. Isotopic composition of ice core air reveals abrupt Antarctic warming during and after Heinrich Event 1a

    Science.gov (United States)

    Morgan, J. D.; Bereiter, B.; Baggenstos, D.; Kawamura, K.; Shackleton, S. A.; Severinghaus, J. P.

    2017-12-01

    Antarctic temperature variations during Heinrich events, as recorded by δ18O­ice­, generally show more gradual changes than the abrupt warmings seen in Greenland ice. However, quantitative temperature interpretation of the water isotope temperature proxy is difficult as the relationship between δ18Oice and temperature is not constant through time. Fortunately, ice cores offer a second temperature proxy based on trapped gases. During times of surface warming, thermal fractionation of gases in the column of unconsolidated snow (firn) on top of the ice sheet results in isotopically heavier nitrogen (N2) and argon (Ar) being trapped in the ice core bubbles. During times of surface cooling, isotopically lighter gases are trapped. Measurements of δ15N and δ40Ar can therefore be used, in combination with a model for the height of the column of firn, to quantitatively reconstruct surface temperatures. In the WAIS Divide Ice Core, the two temperature proxies show a brief disagreement during Heinrich Stadial 1. Despite δ18Oice recording relatively constant temperature, the nitrogen and argon isotopes imply an abrupt warming between 16 and 15.8 kyr BP, manifest as an abrupt 1.25oC increase in the firn temperature gradient. To our knowledge, this would be the first evidence that such abrupt climate change has been recorded in an Antarctic climate proxy. If confirmed by more detailed studies, this event may represent warming due to an extreme southward shift of the Earth's thermal equator (and the southern hemisphere westerly wind belt), caused by the 16.1 ka Heinrich Event.

  15. Records of climatic changes and volcanic events in an ice core from ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    the volcanic event that occurred in 1815 AD, has been identified based on electrical conductance ... tions and accumulation rates of ice, climatic and ..... The peak saturated values of currents (µ amp) at about 5 and 30m depths identify the past volcanic episodes Augung ..... in promoting the scientific activities by allowing us.

  16. The Wunstorf Drilling Project: Coring a Global Stratigraphic Reference Section of the Oceanic Anoxic Event 2

    Directory of Open Access Journals (Sweden)

    Markus Wilmsen

    2007-03-01

    Full Text Available The Wunstorf drilling project aims at establishing a high resolution stable isotope record for the black shale succession (OAE 2 of the CTBI and developing this into a globally applicable high resolutionbio- and chemostratigraphic reference section. Disciplines involved include micropaleontology (calcareous nannofossils, planktonic foraminifera, macropaleontology (ammonites, inoceramids, stable isotopes and cyclostratigraphy mainly based on borehole logging, multisensor core logging, and x-ray flflfluorescence (XRF scanning data. The combination of geochemical, paleontological, and logging data will allow high resolution chemo- and biostratigraphy for the CTBI which may in the future serve as an international standard.

  17. Using CdTe/ZnSe core/shell quantum dots to detect DNA and damage to DNA

    Directory of Open Access Journals (Sweden)

    Moulick A

    2017-02-01

    Full Text Available Amitava Moulick,1,2 Vedran Milosavljevic,1,2 Jana Vlachova,1,2 Robert Podgajny,3 David Hynek,1,2 Pavel Kopel,1,2 Vojtech Adam1,2 1Department of Chemistry and Biochemistry, Mendel University, 2Central European Institute of Technology, Brno University of Technology, Brno, Czech Republic; 3Faculty of Chemistry, Jagiellonian University, Krakow, Poland Abstract: CdTe/ZnSe core/shell quantum dot (QD, one of the strongest and most highly luminescent nanoparticles, was directly synthesized in an aqueous medium to study its individual interactions with important nucleobases (adenine, guanine, cytosine, and thymine in detail. The results obtained from the optical analyses indicated that the interactions of the QDs with different nucleobases were different, which reflected in different fluorescent emission maxima and intensities. The difference in the interaction was found due to the different chemical behavior and different sizes of the formed nanoconjugates. An electrochemical study also confirmed that the purines and pyrimidines show different interactions with the core/shell QDs. Based on these phenomena, a novel QD-based method is developed to detect the presence of the DNA, damage to DNA, and mutation. The QDs were successfully applied very easily to detect any change in the sequence (mutation of DNA. The QDs also showed their ability to detect DNAs directly from the extracts of human cancer (PC3 and normal (PNT1A cells (detection limit of 500 pM of DNA, which indicates the possibilities to use this easy assay technique to confirm the presence of living organisms in extreme environments. Keywords: nanoparticles, nucleobases, biosensor, fluorescence, mutation

  18. Identifying core, exciting, and hybrid attributes in fans' assessments of major (World Cup) spectator sports events.

    Science.gov (United States)

    Gau, Li-Shiue

    2013-12-01

    This paper adopts a methodology of asymmetrical analyses to investigate the relevant importance of spectator sport attributes in terms of their non-linear associations with the benefits that fans experience while watching sports. Questionnaires tapping 16 attributes (e.g., teamwork, sportsmanship, level of competition) and 16 benefits (e.g., good mood, exciting experience, support for my favorite team) were distributed to a sample of fans at the outdoor broadcast of the 2010 World Cup final game at the National Stadium in Kaohsiung, Taiwan. 427 participants rated the importance and benefit of each attribute experienced from watching the game. Attributes were categorized as core, exciting, or hybrid attributes. The star player was the core attribute; rivalry, popularity, and coach were the exciting attributes; and the other 12 attributes were hybrid. Two-dimensional space analyses showed that attributes "sportsmanship, teamwork, and supporting a team" were both explicitly and implicitly important attributes. The methodology of asymmetrical analyses can help managers prioritize the focus of attributes and allocate resources effectively.

  19. Comparison of computer codes relative to the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

    International Nuclear Information System (INIS)

    Fermandjian, J.; Dunbar, I.; Gauvain, J.; Ricchena, R.

    1986-02-01

    The present study concerns a comparative exercise, performed within the framework of the Commission of the European Communities, of the computer codes (AEROSISM-M, UK; AEROSOLS/BI, France; CORRAL-2, CEC and NAUA Mod5, Germany) used in order to assess the aerosol behavior in the reactor containment building during severe core damage accidents in a PWR

  20. Blood pressure variability predicts cardiovascular events independently of traditional cardiovascular risk factors and target organ damage

    DEFF Research Database (Denmark)

    Vishram, Julie K K; Dahlöf, Björn; Devereux, Richard B

    2015-01-01

    ). METHODS: In 8505 patients randomized to losartan vs. atenolol-based treatment in the LIFE study, we tested whether BP variability assessed as SD and range for BP6-24months measured at 6, 12, 18 and 24 months of treatment was associated with target organ damage (TOD) defined by LVH on ECG and urine albumin......BACKGROUND: Assessment of antihypertensive treatment is normally based on the mean value of a number of blood pressure (BP) measurements. However, it is uncertain whether high in-treatment visit-to-visit BP variability may be harmful in hypertensive patients with left ventricular hypertrophy (LVH.......05), but MI was not. CONCLUSION: In LIFE patients, higher in-treatment BP6-24months variability was independently of mean BP6-24months associated with later CEP and stroke, but not with MI or TOD after 24 months....

  1. Initial events in the cellular effects of ionizing radiations: clustered damage in DNA

    International Nuclear Information System (INIS)

    Goodhead, D.T.

    1994-01-01

    Ionizing radiations produce many hundreds of different simple chemical products in DNA and also multitudes of possible clustered combinations. The simple products, including single-strand breaks, tend to correlate poorly with biological effectiveness. Even for initial double-strand breaks, as a broad class, there is apparently little or no increase in yield with increasing ionization density, in contrast with the large rise in relative biological effectiveness for cellular effects. Track structure analysis has revealed that clustered DNA damage of severity greater than simple double-strand breaks is likely to occur at biologically relevant frequencies with all ionizing radiations. Studies are in progress to describe in more detail the chemical nature of these clustered lesions and to consider the implications for cellular repair. (author)

  2. Contribution of insurance data to cost assessment of coastal flood damage to residential buildings: insights gained from Johanna (2008 and Xynthia (2010 storm events

    Directory of Open Access Journals (Sweden)

    C. André

    2013-08-01

    Full Text Available There are a number of methodological issues involved in assessing damage caused by natural hazards. The first is the lack of data, due to the rarity of events and the widely different circumstances in which they occur. Thus, historical data, albeit scarce, should not be neglected when seeking to build ex-ante risk management models. This article analyses the input of insurance data for two recent severe coastal storm events, to examine what causal relationships may exist between hazard characteristics and the level of damage incurred by residential buildings. To do so, data was collected at two levels: from lists of about 4000 damage records, 358 loss adjustment reports were consulted, constituting a detailed damage database. The results show that for flooded residential buildings, over 75% of reconstruction costs are associated with interior elements, with damage to structural components remaining very localised and negligible. Further analysis revealed a high scatter between costs and water depth, suggesting that uncertainty remains high in drawing up damage functions with insurance data alone. Due to the paper format of the loss adjustment reports, and the lack of harmonisation between their contents, the collection stage called for a considerable amount of work. For future events, establishing a standardised process for archiving damage information could significantly contribute to the production of such empirical damage functions. Nevertheless, complementary sources of data on hazards and asset vulnerability parameters will definitely still be necessary for damage modelling; multivariate approaches, crossing insurance data with external material, should also be investigated more deeply.

  3. Contribution of insurance data to cost assessment of coastal flood damage to residential buildings: insights gained from Johanna (2008) and Xynthia (2010) storm events

    Science.gov (United States)

    André, C.; Monfort, D.; Bouzit, M.; Vinchon, C.

    2013-08-01

    There are a number of methodological issues involved in assessing damage caused by natural hazards. The first is the lack of data, due to the rarity of events and the widely different circumstances in which they occur. Thus, historical data, albeit scarce, should not be neglected when seeking to build ex-ante risk management models. This article analyses the input of insurance data for two recent severe coastal storm events, to examine what causal relationships may exist between hazard characteristics and the level of damage incurred by residential buildings. To do so, data was collected at two levels: from lists of about 4000 damage records, 358 loss adjustment reports were consulted, constituting a detailed damage database. The results show that for flooded residential buildings, over 75% of reconstruction costs are associated with interior elements, with damage to structural components remaining very localised and negligible. Further analysis revealed a high scatter between costs and water depth, suggesting that uncertainty remains high in drawing up damage functions with insurance data alone. Due to the paper format of the loss adjustment reports, and the lack of harmonisation between their contents, the collection stage called for a considerable amount of work. For future events, establishing a standardised process for archiving damage information could significantly contribute to the production of such empirical damage functions. Nevertheless, complementary sources of data on hazards and asset vulnerability parameters will definitely still be necessary for damage modelling; multivariate approaches, crossing insurance data with external material, should also be investigated more deeply.

  4. Evidence for nucleosynthetic enrichment of the protosolar molecular cloud core by multiple supernova events

    DEFF Research Database (Denmark)

    Schiller, Martin; Paton, Chad; Bizzarro, Martin

    2015-01-01

    The presence of isotope heterogeneity of nucleosynthetic origin amongst meteorites and their components provides a record of the diverse stars that contributed matter to the protosolar molecular cloud core. Understanding how and when the solar system's nucleosynthetic heterogeneity was established...... and preserved within the solar protoplanetary disk is critical for unraveling the earliest formative stages of the solar system. Here, we report calcium and magnesium isotope measurements of primitive and differentiated meteorites as well as various types of refractory inclusions, including refractory...... and differentiated meteorites along with canonical and FUN-CAIs define correlated, mass-independent variations in 43Ca, 46Ca and 48Ca. Moreover, sequential dissolution experiments of the Ivuna carbonaceous chondrite aimed at identifying the nature and number of presolar carriers of isotope anomalies within primitive...

  5. Calcific aortic valve damage as a risk factor for cardiovascular events

    International Nuclear Information System (INIS)

    Wasilewski, Jarosław; Mirota, Kryspin; Wilczek, Krzysztof; Głowacki, Jan; Poloński, Lech

    2012-01-01

    Aortic valve calcification (AVC) is a common disease of the elderly. It is a progressive disease ranging from mild valve thickening to severe calcification with aortic valve stenosis. Risk factors for AVC are similar to those for atherosclerosis: age, gender, hypercholesterolemia, diabetes, hypertension, smoking and renal failure. AVC shares many similarities to atherosclerosis, including inflammatory cells and calcium deposits, and correlates with coronary plaque burden. Presence of AVC is associated with increased risk of adverse cardiovascular events. The objective for this review is to discuss the clinical features, natural history and prognostic significance of aortic valve calcifications, including mechanical and hemodynamic factors of flow distribution

  6. Modeling early physical and chemical events for DNA damage induced by photons and tritium beta particles

    International Nuclear Information System (INIS)

    Moiseenko, V.; Waker, A.J.; Prestwich, W.V.

    1998-02-01

    A method has been developed to model production of single-strand breaks (SSB) and double-strand breaks (DSB) in Deoxyribo Nucleic Acid (DNA) by ionizing radiations. Modeling is carried out by Monte Carlo means and includes consideration of direct energy depositions in DNA molecules, production of chemical species following water radiolysis, diffusion of chemical species, and their interactions with each other and DNA. Computer-generated electron tracks in liquid water are used to model energy deposition and to derive the initial localization of chemical species. Atomistic representation of the DNA with a first hydration shell is used to derive direct energy depositions in DNA molecules and the resulting consequences, and to derive coordinates of reactive sites for modeling of the chemical stage of radiation damage. Diffusion of chemical species is followed in time, and the reactions of species with each other and DNA are considered to occur in an encounter-controlled manner. Time of diffusion follow-up is restricted to 10 -12 - 10 -9 s, which yields a diffusion length of hydroxyl radicals comparable to that in the cellular environment. DNA SSB are assumed to result from any direct energy depositions in the sugar/phosphate moiety, ionizations in water molecules bound to sugar/phosphate and hydroxyl attacks on deoxyribose. DSB are assumed to result from two SSB on opposite strands separated by 10 or fewer base pairs. Photon radiations in the energy range 70 keV-1 MeV and tritium beta particles are considered. It is shown that for naked DNA in B-form (the configuration thought to be most biologically relevant) the effectiveness of tritium for SSB and DSB production is, within statistical uncertainties, comparable to photon radiation with energies in the range 70 keV-1 MeV, although a tendency for increased DSB production has been observed for 70 keV photons that represent orthovoltage X-rays and for tritium beta particles. It is predicted that hydroxyl radicals react

  7. Modeling early physical and chemical events for DNA damage induced by photons and tritium beta particles

    Energy Technology Data Exchange (ETDEWEB)

    Moiseenko, V [McMaster Univ., Dept. of Physics and Astronomy, Hamilton, Ontario (Canada); Waker, A J [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Prestwich, W V [McMaster Univ., Dept. of Physics and Astronomy, Hamilton, Ontario (Canada)

    1998-02-01

    A method has been developed to model production of single-strand breaks (SSB) and double-strand breaks (DSB) in Deoxyribo Nucleic Acid (DNA) by ionizing radiations. Modeling is carried out by Monte Carlo means and includes consideration of direct energy depositions in DNA molecules, production of chemical species following water radiolysis, diffusion of chemical species, and their interactions with each other and DNA. Computer-generated electron tracks in liquid water are used to model energy deposition and to derive the initial localization of chemical species. Atomistic representation of the DNA with a first hydration shell is used to derive direct energy depositions in DNA molecules and the resulting consequences, and to derive coordinates of reactive sites for modeling of the chemical stage of radiation damage. Diffusion of chemical species is followed in time, and the reactions of species with each other and DNA are considered to occur in an encounter-controlled manner. Time of diffusion follow-up is restricted to 10{sup -12}- 10{sup -9} s, which yields a diffusion length of hydroxyl radicals comparable to that in the cellular environment. DNA SSB are assumed to result from any direct energy depositions in the sugar/phosphate moiety, ionizations in water molecules bound to sugar/phosphate and hydroxyl attacks on deoxyribose. DSB are assumed to result from two SSB on opposite strands separated by 10 or fewer base pairs. Photon radiations in the energy range 70 keV-1 MeV and tritium beta particles are considered. It is shown that for naked DNA in B-form (the configuration thought to be most biologically relevant) the effectiveness of tritium for SSB and DSB production is, within statistical uncertainties, comparable to photon radiation with energies in the range 70 keV-1 MeV, although a tendency for increased DSB production has been observed for 70 keV photons that represent orthovoltage X-rays and for tritium beta particles. It is predicted that hydroxyl

  8. Application of Continuous and Structural ARMA modeling for noise analysis of a BWR coupled core and plant instability event

    International Nuclear Information System (INIS)

    Demeshko, M.; Dokhane, A.; Washio, T.; Ferroukhi, H.; Kawahara, Y.; Aguirre, C.

    2015-01-01

    Highlights: • We demonstrate the first application of a novel CSARMA method. • We analyze the instability occurred in a Swiss BWR plant during power ascension. • Benchmarked the results against STP analysis. • The CSARMA results are consistent with the background physics and the STP results. • The instability was caused by disturbances in the pressure control system. - Abstract: This paper presents a first application of a novel Continuous and Structural Autoregressive Moving Average (CSARMA) modeling approach to BWR noise analysis. The CSARMA approach derives a unique representation of the system dynamics by more robust and reliable canonical models as basis for signal analysis in general and for reactor diagnostics in particular. In this paper, a stability event that occurred in a Swiss BWR plant during power ascension phase is analyzed as well as the time periods that preceded and followed the event. Focusing only on qualitative trends at this stage, the obtained results clearly indicate a different dynamical state during the unstable event compared to the two other stable periods. Also, they could be interpreted as pointing out a disturbance in the pressure control system as primary cause for the event. To benchmark these findings, the frequency-domain based signal transmission-path (STP) method is also applied. And with the STP method, we obtained similar relationships as mentioned above. This consistency between both methods can be considered as being a confirmation that the event was caused by a pressure control system disturbance and not induced by the core. Also, it is worth noting that the STP analysis failed to catch the relations among the processes during the stable periods, that were clearly indicated by the CSARMA method, since the last uses more precise models as basis

  9. Intensity earthquake scenario (scenario event - a damaging earthquake with higher probability of occurrence) for the city of Sofia

    Science.gov (United States)

    Aleksandrova, Irena; Simeonova, Stela; Solakov, Dimcho; Popova, Maria

    2014-05-01

    Among the many kinds of natural and man-made disasters, earthquakes dominate with regard to their social and economical impact on the urban environment. Global seismic risk to earthquakes are increasing steadily as urbanization and development occupy more areas that a prone to effects of strong earthquakes. Additionally, the uncontrolled growth of mega cities in highly seismic areas around the world is often associated with the construction of seismically unsafe buildings and infrastructures, and undertaken with an insufficient knowledge of the regional seismicity peculiarities and seismic hazard. The assessment of seismic hazard and generation of earthquake scenarios is the first link in the prevention chain and the first step in the evaluation of the seismic risk. The earthquake scenarios are intended as a basic input for developing detailed earthquake damage scenarios for the cities and can be used in earthquake-safe town and infrastructure planning. The city of Sofia is the capital of Bulgaria. It is situated in the centre of the Sofia area that is the most populated (the population is of more than 1.2 mil. inhabitants), industrial and cultural region of Bulgaria that faces considerable earthquake risk. The available historical documents prove the occurrence of destructive earthquakes during the 15th-18th centuries in the Sofia zone. In 19th century the city of Sofia has experienced two strong earthquakes: the 1818 earthquake with epicentral intensity I0=8-9 MSK and the 1858 earthquake with I0=9-10 MSK. During the 20th century the strongest event occurred in the vicinity of the city of Sofia is the 1917 earthquake with MS=5.3 (I0=7-8 MSK). Almost a century later (95 years) an earthquake of moment magnitude 5.6 (I0=7-8 MSK) hit the city of Sofia, on May 22nd, 2012. In the present study as a deterministic scenario event is considered a damaging earthquake with higher probability of occurrence that could affect the city with intensity less than or equal to VIII

  10. Comprehensive simulation of vertical plasma instability events and their serious damage to ITER plasma facing components

    International Nuclear Information System (INIS)

    Hassanein, A.; Sizyuk, T.

    2008-01-01

    Safe and reliable operation is still one of the major challenges in the development of the new generation of ITER-like fusion reactors. The deposited plasma energy during major disruptions, edge-localized modes (ELMs) and vertical displacement events (VDEs) causes significant surface erosion, possible structural failure and frequent plasma contamination. While plasma disruptions and ELM will have no significant thermal effects on the structural materials or coolant channels because of their short deposition time, VDEs having longer-duration time could have a destructive impact on these components. Therefore, modelling the response of structural materials to VDE has to integrate detailed energy deposition processes, surface vaporization, phase change and melting, heat conduction to coolant channels and critical heat flux criteria at the coolant channels. The HEIGHTS 3D upgraded computer package considers all the above processes to specifically study VDE in detail. Results of benchmarking with several known laboratory experiments prove the validity of HEIGHTS implemented models. Beryllium and tungsten are both considered surface coating materials along with copper structure and coolant channels using both smooth tubes with swirl tape insert. The design requirements and implications of plasma facing components are discussed along with recommendations to mitigate and reduce the effects of plasma instabilities on reactor components.

  11. Multitemporal 3d Modelling for Cultural Heritage Emergency during Seismic Events: Damage Assesment of S. Agostino Church in Amatrice (ri)

    Science.gov (United States)

    Chiabrando, F.; Di Lolli, A.; Patrucco, G.; Spanò, A.; Sammartano, G.; Teppati Losè, L.

    2017-05-01

    One of the challenging purposes that must be undertaken by applied geomatics, is the need of monitoring by documenting continuously over time the evolution of urban spaces. Nowadays, this is a subject of great interest and study, mainly in case of sudden emergency events that implicate urban areas and specific historical buildings of our heritage. The newest Geomatics technique solutions must enable the demands of damage documentation, risk assessment, management and data sharing as efficiently as possible, in relation to the danger condition, to the accessibility constraints of areas and to the tight deadlines needs. In August 24th 2016, the first earthquake hit the area of central Italy with a magnitude of 6.0; since then, the earth never stop shaking in a wide area in the middle of Italy. On 26th and 30th of October, two other big seismic events were recorded (magnitude 5.9 and 6.5) and the already damaged built heritage were struck again. Since the beginning of the emergency all the available resources (human and material) were deployed and the world of researchers is trying to furnish an effective contribute as well. Politecnico di Torino, in coordination with the national institutions, is deploying people, expertise and resources. The geomatics research group and the connected Disaster Recovery team (DIRECT - http://areeweb.polito.it/direct/) is part of this process and is working in deep contact and collaboration with the Remotely Piloted Aircraft Systems (RPAS) group of the Italian Firefighter. Starting from the first earthquake the late medieval religious complex of S. Agostino has been carefully monitored and detected, using a multi-perspective oblique imagery strategy with the aim to achieve 3D aerial and terrestrial models, in a multi-temporal perspective concerning three different time situation.

  12. MULTITEMPORAL 3D MODELLING FOR CULTURAL HERITAGE EMERGENCY DURING SEISMIC EVENTS: DAMAGE ASSESMENT OF S. AGOSTINO CHURCH IN AMATRICE (RI

    Directory of Open Access Journals (Sweden)

    F. Chiabrando

    2017-05-01

    Full Text Available One of the challenging purposes that must be undertaken by applied geomatics, is the need of monitoring by documenting continuously over time the evolution of urban spaces. Nowadays, this is a subject of great interest and study, mainly in case of sudden emergency events that implicate urban areas and specific historical buildings of our heritage. The newest Geomatics technique solutions must enable the demands of damage documentation, risk assessment, management and data sharing as efficiently as possible, in relation to the danger condition, to the accessibility constraints of areas and to the tight deadlines needs. In August 24th 2016, the first earthquake hit the area of central Italy with a magnitude of 6.0; since then, the earth never stop shaking in a wide area in the middle of Italy. On 26th and 30th of October, two other big seismic events were recorded (magnitude 5.9 and 6.5 and the already damaged built heritage were struck again. Since the beginning of the emergency all the available resources (human and material were deployed and the world of researchers is trying to furnish an effective contribute as well. Politecnico di Torino, in coordination with the national institutions, is deploying people, expertise and resources. The geomatics research group and the connected Disaster Recovery team (DIRECT - http://areeweb.polito.it/direct/ is part of this process and is working in deep contact and collaboration with the Remotely Piloted Aircraft Systems (RPAS group of the Italian Firefighter. Starting from the first earthquake the late medieval religious complex of S. Agostino has been carefully monitored and detected, using a multi-perspective oblique imagery strategy with the aim to achieve 3D aerial and terrestrial models, in a multi-temporal perspective concerning three different time situation.

  13. Comparison of european computer codes relative to the aerosol behavior in PWR containment buildings during severe core damage accidents. (Modelling of steam condensation on the particles)

    International Nuclear Information System (INIS)

    Bunz, H.; Dunbar, L.H.; Fermandjian, J.; Lhiaubet, G.

    1987-11-01

    An aerosol code comparison exercise was performed within the framework of the Commission of European Communities (Division of Safety of Nuclear Installations). This exercise, focused on the process of steam condensation onto the aerosols occurring in PWR containment buildings during severe core damage accidents, has allowed to understand the discrepancies between the results obtained. These discrepancies are due, in particular, to whether the curvature effect is modelled or not in the codes

  14. Events

    Directory of Open Access Journals (Sweden)

    Igor V. Karyakin

    2016-02-01

    Full Text Available The 9th ARRCN Symposium 2015 was held during 21st–25th October 2015 at the Novotel Hotel, Chumphon, Thailand, one of the most favored travel destinations in Asia. The 10th ARRCN Symposium 2017 will be held during October 2017 in the Davao, Philippines. International Symposium on the Montagu's Harrier (Circus pygargus «The Montagu's Harrier in Europe. Status. Threats. Protection», organized by the environmental organization «Landesbund für Vogelschutz in Bayern e.V.» (LBV was held on November 20-22, 2015 in Germany. The location of this event was the city of Wurzburg in Bavaria.

  15. An Assessment of Fission Product Scrubbing in Sodium Pools Following a Core Damage Event in a Sodium Cooled Fast Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Bucknor, M.; Farmer, M.; Grabaskas, D.

    2017-06-26

    The U.S. Nuclear Regulatory Commission has stated that mechanistic source term (MST) calculations are expected to be required as part of the advanced reactor licensing process. A recent study by Argonne National Laboratory has concluded that fission product scrubbing in sodium pools is an important aspect of an MST calculation for a sodium-cooled fast reactor (SFR). To model the phenomena associated with sodium pool scrubbing, a computational tool, developed as part of the Integral Fast Reactor (IFR) program, was utilized in an MST trial calculation. This tool was developed by applying classical theories of aerosol scrubbing to the decontamination of gases produced as a result of postulated fuel pin failures during an SFR accident scenario. The model currently considers aerosol capture by Brownian diffusion, inertial deposition, and gravitational sedimentation. The effects of sodium vapour condensation on aerosol scrubbing are also treated. This paper provides details of the individual scrubbing mechanisms utilized in the IFR code as well as results from a trial mechanistic source term assessment led by Argonne National Laboratory in 2016.

  16. Contribution of insurance data to cost assessment of coastal flood damage to residential buildings: insights gained from Johanna (2008) and Xynthia (2010) storm events

    OpenAIRE

    C. André; D. Monfort; M. Bouzit; C. Vinchon

    2013-01-01

    There are a number of methodological issues involved in assessing damage caused by natural hazards. The first is the lack of data, due to the rarity of events and the widely different circumstances in which they occur. Thus, historical data, albeit scarce, should not be neglected when seeking to build ex-ante risk management models. This article analyses the input of insurance data for two recent severe coastal storm events, to examine what causal relationships may exist bet...

  17. Visualization of chromatin events associated with repair of ultraviolet light-induced damage by premature chromosome condensation

    International Nuclear Information System (INIS)

    Hittelman, W.N.; Pollard, M.

    1984-01-01

    Quiescent normal human fibroblasts were irradiated with u.v. and the ensuing chromatin events were visualised by inducing premature chromosome condensation in the treated cells. Treatment with u.v. induced 1) a generalised elongation of the Gl premature condensed chromosomes (PCC) and 2) regions of localized elongation or gaps. The degree of chromatin change was dose dependent and could be seen immediately after irradiation. The generalised elongation process continued to increase for 24 h after irradiation, suggesting it represented a cellular reaction to the u.v.-induced damage, rather than a direct physical distortion. The localized decondensation reaction was associated with the site of unscheduled DNA synthesis. Post-treatment incubation of cells in the presence of cytosine arabinoside and hydroxyurea resulted in an accumulation of gaps. The inhibitor novobiocin predominantly inhibited the formation of gap regions, suggesting that a topoisomerase-like reaction might be important in their formation. The presence of cycloheximide after u.v. irradiation had no effect on the chromatin changes, suggesting that no new protein synthesis is required for these chromatin processes associated with repair. These results suggest that the PCC technique is useful in elucidating chromatin changes associated with DNA repair after u.v. treatment. (author)

  18. Agricultural losses related to frost events: use of the 850 hPa level temperature as an explanatory variable of the damage cost

    Science.gov (United States)

    Papagiannaki, K.; Lagouvardos, K.; Kotroni, V.; Papagiannakis, G.

    2014-09-01

    The objective of this study is the analysis of damaging frost events in agriculture, by examining the relationship between the daily minimum temperature in the lower atmosphere (at an isobaric level of 850 hPa) and crop production losses. Furthermore, the study suggests a methodological approach for estimating agriculture risk due to frost events, with the aim of estimating the short-term probability and magnitude of frost-related financial losses for different levels of 850 hPa temperature. Compared with near-surface temperature forecasts, temperature forecasts at the level of 850 hPa are less influenced by varying weather conditions or by local topographical features; thus, they constitute a more consistent indicator of the forthcoming weather conditions. The analysis of the daily monetary compensations for insured crop losses caused by weather events in Greece shows that, during the period 1999-2011, frost caused more damage to crop production than any other meteorological phenomenon. Two regions of different geographical latitudes are examined further, to account for the differences in the temperature ranges developed within their ecological environment. Using a series of linear and logistic regressions, we found that minimum temperature (at an 850 hPa level), grouped into three categories according to its magnitude, and seasonality, are significant variables when trying to explain crop damage costs, as well as to predict and quantify the likelihood and magnitude of damaging frost events.

  19. Sensitivity Analysis of Core Damage from Reactor Coolant Pump Seal Leakage during Extended Loss of All AC Power

    Energy Technology Data Exchange (ETDEWEB)

    Park, Da Hee; Kim, Min Gi; Lee, Kyung Jin; Hwang, Su hyun; Lee, Byung Chul [FNC Technology Co. Ltd., Yongin (Korea, Republic of); Yoon, Duk Joo; Lee, Seung Chan [Korea Hydro and Nuclear Power Co. Ltd., Daejeon (Korea, Republic of)

    2015-10-15

    In this study, in order to comprehend the Fukushima accident, the sensitivity analysis was performed to analyze the behavior of Reactor Coolant System (RCS) during ELAP using the RELAP5/MOD3.3 code. The Fukushima accident was caused by tsunami resulted in Station Black Out (SBO) followed by the reactor core melt-down and release of radioactive materials. After the accident, the equipment and strategies for the Extended Loss of All AC Power (ELAP) were recommended strongly. In this analysis, sensitivity studies for the RCP seal failure of the OPR1000 type NPP were performed by using RELAP5/MOD3.3 code. Six cases with different leakage rate of RCP seal were studied for ELAP with operator action or not. The main findings are summarized as follows: (1) Without the operator action, the core uncovery time is determined by the leakage rate of RCP seal. When the leakage rate per RCP seal are 5 gpm, 50 gpm, and 300 gpm respectively, the core uncovery time are 1.62 hr, 1.58 hr, and 1.29 hr respectively. Namely, If the leakage rate of RCP seal was much bigger, the uncover time of core would be shorter. (2) In case that the cooling by SG secondary side was performed using the TDAFP and SG ADV, the core uncovery time was significantly extended.

  20. Magnetohydrodynamic behaviour during core transport barrier experiments with ion Bernstein wave heating in PBX-M: I ELMs fluctuations and crash events

    International Nuclear Information System (INIS)

    Sesnic, S.; Kaita, R.; Batha, S.H.

    1998-01-01

    linear ion temperature gradient (ITG) growth rate. The presence of the core barrier region also strongly modifies the other MHD events: crashes on the q=1.5, 2 surfaces and the disruption. (author)

  1. Haloperidol-loaded lipid-core polymeric nanocapsules reduce DNA damage in blood and oxidative stress in liver and kidneys of rats

    International Nuclear Information System (INIS)

    Roversi, Katiane; Benvegnú, Dalila M.; Roversi, Karine; Trevizol, Fabíola; Vey, Luciana T.; Elias, Fabiana; Fracasso, Rafael

    2015-01-01

    Haloperidol (HP) nanoencapsulation improves therapeutic efficacy, prolongs the drug action time, and reduces its motor side effects. However, in a view of HP toxicity in organs like liver and kidneys in addition to the lack of knowledge regarding the toxicity of polymeric nanocapsules, our aim was to verify the influence of HP-nanoformulation on toxicity and oxidative stress markers in the liver and kidneys of rats, also observing the damage caused in the blood. For such, 28 adult male Wistar rats were designated in four experimental groups (n = 7) and treated with vehicle (C group), free haloperidol suspension (FH group), blank nanocapsules suspension (B-Nc group), and haloperidol-loaded lipid-core nanocapsules suspension (H-Nc group). The nanocapsules formulation presented the size of approximately 250 nm. All suspensions were administered to the animals (0.5 mg/kg/day-i.p.) for a period of 28 days. Our results showed that FH caused damage in the liver, evidenced by increased lipid peroxidation, plasma levels of aspartate aminotransferase, and alanine aminotransferase, as well as decreased cellular integrity and vitamin C levels. In kidneys, FH treatment caused damage to a lesser extent, observed by decreased activity of δ-aminolevulinate dehydratase (ALA-D) and levels of VIT C. In addition, FH treatment was also related to a higher DNA damage index in blood. On the other hand, animals treated with H-Nc and B-Nc did not show damage in liver, kidneys, and DNA. Our study indicates that the nanoencapsulation of haloperidol was able to prevent the sub-chronic toxicity commonly observed in liver, kidneys, and DNA, thus reflecting a pharmacological superiority in relation to free drug

  2. Haloperidol-loaded lipid-core polymeric nanocapsules reduce DNA damage in blood and oxidative stress in liver and kidneys of rats

    Science.gov (United States)

    Roversi, Katiane; Benvegnú, Dalila M.; Roversi, Karine; Trevizol, Fabíola; Vey, Luciana T.; Elias, Fabiana; Fracasso, Rafael; Motta, Mariana H.; Ribeiro, Roseane F.; dos S. Hausen, Bruna; Moresco, Rafael N.; Garcia, Solange C.; da Silva, Cristiane B.; Burger, Marilise E.

    2015-04-01

    Haloperidol (HP) nanoencapsulation improves therapeutic efficacy, prolongs the drug action time, and reduces its motor side effects. However, in a view of HP toxicity in organs like liver and kidneys in addition to the lack of knowledge regarding the toxicity of polymeric nanocapsules, our aim was to verify the influence of HP-nanoformulation on toxicity and oxidative stress markers in the liver and kidneys of rats, also observing the damage caused in the blood. For such, 28 adult male Wistar rats were designated in four experimental groups ( n = 7) and treated with vehicle (C group), free haloperidol suspension (FH group), blank nanocapsules suspension (B-Nc group), and haloperidol-loaded lipid-core nanocapsules suspension (H-Nc group). The nanocapsules formulation presented the size of approximately 250 nm. All suspensions were administered to the animals (0.5 mg/kg/day-i.p.) for a period of 28 days. Our results showed that FH caused damage in the liver, evidenced by increased lipid peroxidation, plasma levels of aspartate aminotransferase, and alanine aminotransferase, as well as decreased cellular integrity and vitamin C levels. In kidneys, FH treatment caused damage to a lesser extent, observed by decreased activity of δ-aminolevulinate dehydratase (ALA-D) and levels of VIT C. In addition, FH treatment was also related to a higher DNA damage index in blood. On the other hand, animals treated with H-Nc and B-Nc did not show damage in liver, kidneys, and DNA. Our study indicates that the nanoencapsulation of haloperidol was able to prevent the sub-chronic toxicity commonly observed in liver, kidneys, and DNA, thus reflecting a pharmacological superiority in relation to free drug.

  3. Haloperidol-loaded lipid-core polymeric nanocapsules reduce DNA damage in blood and oxidative stress in liver and kidneys of rats

    Energy Technology Data Exchange (ETDEWEB)

    Roversi, Katiane, E-mail: katianeroversi@gmail.com [Universidade Federal de Santa Maria, Programa de Pós-Graduação em Farmacologia (Brazil); Benvegnú, Dalila M., E-mail: dalilabenvegnu@yahoo.com.br [Universidade Federal da Fronteira Sul (UFFS), Bioquímica e Farmacologia (Brazil); Roversi, Karine, E-mail: karineroversi-@hotmail.com [Universidade Federal de Santa Maria (UFSM), Departamento de Fisiologia e Farmacologia, Centro de Ciências da Saúde (Brazil); Trevizol, Fabíola, E-mail: fatrevizol@yahoo.com.br [Universidade Federal de Santa Maria, Programa de Pós-Graduação em Farmacologia (Brazil); Vey, Luciana T., E-mail: luciana.taschetto@hotmail.com [Universidade Federal de Santa Maria (UFSM), Departamento de Fisiologia e Farmacologia, Centro de Ciências da Saúde (Brazil); Elias, Fabiana, E-mail: fabiana.elias@uffs.edu.br [Universidade Federal da Fronteira Sul (UFFS), Bioquímica e Farmacologia (Brazil); Fracasso, Rafael, E-mail: rafael.fra@hotmail.com [Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Ciências Farmacêuticas (Brazil); and others

    2015-04-15

    Haloperidol (HP) nanoencapsulation improves therapeutic efficacy, prolongs the drug action time, and reduces its motor side effects. However, in a view of HP toxicity in organs like liver and kidneys in addition to the lack of knowledge regarding the toxicity of polymeric nanocapsules, our aim was to verify the influence of HP-nanoformulation on toxicity and oxidative stress markers in the liver and kidneys of rats, also observing the damage caused in the blood. For such, 28 adult male Wistar rats were designated in four experimental groups (n = 7) and treated with vehicle (C group), free haloperidol suspension (FH group), blank nanocapsules suspension (B-Nc group), and haloperidol-loaded lipid-core nanocapsules suspension (H-Nc group). The nanocapsules formulation presented the size of approximately 250 nm. All suspensions were administered to the animals (0.5 mg/kg/day-i.p.) for a period of 28 days. Our results showed that FH caused damage in the liver, evidenced by increased lipid peroxidation, plasma levels of aspartate aminotransferase, and alanine aminotransferase, as well as decreased cellular integrity and vitamin C levels. In kidneys, FH treatment caused damage to a lesser extent, observed by decreased activity of δ-aminolevulinate dehydratase (ALA-D) and levels of VIT C. In addition, FH treatment was also related to a higher DNA damage index in blood. On the other hand, animals treated with H-Nc and B-Nc did not show damage in liver, kidneys, and DNA. Our study indicates that the nanoencapsulation of haloperidol was able to prevent the sub-chronic toxicity commonly observed in liver, kidneys, and DNA, thus reflecting a pharmacological superiority in relation to free drug.

  4. Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage

    International Nuclear Information System (INIS)

    Noda, Taichi; Takahashi, Akihisa; Kondo, Natsuko; Mori, Eiichiro; Okamoto, Noritomo; Nakagawa, Yosuke; Ohnishi, Ken; Zdzienicka, Malgorzata Z.; Thompson, Larry H.; Helleday, Thomas; Asada, Hideo

    2011-01-01

    The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA -/- , FANCC -/- , FANCA -/- C -/- , FANCD2 -/- and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical γH2AX-staining assay. Although the sensitivity of FANCA -/- , FANCC -/- and FANCA -/- C -/- cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2 -/- cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, γH2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex. -- Research highlights: → We examined to clarify the repair pathways of formaldehyde-induced DNA damage. Formaldehyde induces DNA double strand breaks (DSBs). → DSBs are repaired through the Fanconi anemia (FA) repair pathway. → This pathway is independent of the FA nuclear core complex. → We also found that homologous recombination repair was induced by formaldehyde.

  5. Assessment of fission product release from the reactor containment building during severe core damage accidents in a PWR

    International Nuclear Information System (INIS)

    Fermandjian, J.; Evrard, J.M.; Generino, G.

    1984-07-01

    Fission product releases from the RCB associated with hypothetical core-melt accidents ABβ, S 2 CDβ and TLBβ in a PWR-900 MWe have been performed using French computer codes (in particular, the JERICHO Code for containment response analysis and AEROSOLS/B1 for aerosol behavior in the containment) related to thermalhydraulics and fission product behavior in the primary system and in the reactor containment building

  6. Assessment of core damage models in SCDAP/RELAP5 during OECD LOFT LP-FP-2

    International Nuclear Information System (INIS)

    Coryell, E.W.

    1991-01-01

    The US Nuclear Regulatory Commission has sponsored a program to apply the SCDAP/RELAP5 code to analysis of the transient and reflood phases of the OECD LOFT LP-FP-2 Experiment. The principal objectives of the LP-FP-2 experiment were to determine the fission product release from the fuel during the early phases of a severe fuel damage scenario and to examine the phenomena controlling fission product transport in a vapor/aerosol environment. Calculations with the SCDAP/RELAP5 code, developed at the INEL with NRC support, have been performed to (1) examine the phenomena controlling the progression of both transient and reflood phases of the experiment, (2) enhance our understanding of the phenomena occurring during reflood and add credence to the postulated phenomenological sequence, (3) assess the ability of SCDAP/RELAP5 to examine severe fuel damage issues and phenomena, and (4) identify code strengths and deficiencies with the intent of prioritizing code improvements. Results indicate that the code is able to analyze the early phases of severe fuel damage reasonably well, with potential deficiencies in modelling interaction between molten control rod material and intact fuel

  7. Top event prevention analysis: A deterministic use of PRA

    International Nuclear Information System (INIS)

    Worrell, R.B.; Blanchard, D.P.

    1996-01-01

    This paper describes the application of Top Event Prevention Analysis. The analysis finds prevention sets which are combinations of basic events that can prevent the occurrence of a fault tree top event such as core damage. The problem analyzed in this application is that of choosing a subset of Motor-Operated Valves (MOVs) for testing under the Generic Letter 89-10 program such that the desired level of safety is achieved while providing economic relief from the burden of testing all safety-related valves. A brief summary of the method is given, and the process used to produce a core damage expression from Level 1 PRA models for a PWR is described. The analysis provides an alternative to the use of importance measures for finding the important combination of events in a core damage expression. This application of Top Event Prevention Analysis to the MOV problem was achieve with currently available software

  8. On-site releases of noble gases and iodine in the event of core meltdown in a swimming pool reactor

    International Nuclear Information System (INIS)

    Montaignac, E. de.

    1976-10-01

    Research aimed at defining a standard model accident for swimming pool type reactors, has led to the adoption to the so-called BORAX accident which involves complete meltdown of the reactor core. This type of accident-an accident related to dimensional problems- is useful for calculations concerning reactor components which have to withstand the mechanical forces resulting from the accident. A study of the radiobiological consequences of this type of accident, involving the entire reactor core, required research to determine as accurately as possible how the iodine, noble gases and solid fission products are distributed between the melted core and the site. The joint document in the annexure served as the basis for discussion at the meeting (BEVS/SESR) on 9th March 1973, at which the SESR set the standard parameter values to be used for estimating fission product distributions on the site. (author)

  9. Preliminary Assessment of the Possible BWR Core/Vessel Damage States for Fukushima Daiichi Station Blackout Scenarios Using RELAP/SCDAPSIM

    Directory of Open Access Journals (Sweden)

    C. M. Allison

    2012-01-01

    Full Text Available Immediately after the accident at Fukushima Daiichi, Innovative Systems Software and other members of the international SCDAP Development and Training Program started an assessment of the possible core/vessel damage states of the Fukushima Daiichi Units 1–3. The assessment included a brief review of relevant severe accident experiments and a series of detailed calculations using RELAP/SCDAPSIM. The calculations used a detailed RELAP/SCDAPSIM model of the Laguna Verde BWR vessel and related reactor cooling systems. The Laguna Verde models were provided by the Comision Nacional de Seguridad Nuclear y Salvaguardias, the Mexican nuclear regulatory authority. The initial assessment was originally presented to the International Atomic Energy Agency on March 21 to support their emergency response team and later to our Japanese members to support their Fukushima Daiichi specific analysis and model development.

  10. Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Taichi [Department of Biology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Department of Dermatology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Takahashi, Akihisa [Department of Biology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Kondo, Natsuko [Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494 (Japan); Mori, Eiichiro [Department of Biology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Okamoto, Noritomo [Department of Otorhinolaryngology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Nakagawa, Yosuke [Department of Oral and Maxillofacial Surgery, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); Ohnishi, Ken [Department of Biology, Ibaraki Prefectual University of Health Sciences, 4669-2 Ami, Ami-mati, Inasiki-gun, Ibaraki 300-0394 (Japan); Zdzienicka, Malgorzata Z. [Department of Molecular Cell Genetics, Collegium Medicum in Bydgoszcz, Nicolaus-Copernicus-University in Torun, ul. Sklodowskiej-Curie 9, 85-094 Bydgoszcz (Poland); Thompson, Larry H. [Biosciences and Biotechnology Division, L452, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA 94551-0808 (United States); Helleday, Thomas [Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Off Roosevelt Drive, Oxford, OX3 7DQ (United Kingdom); Department of Genetics, Microbiology and Toxicology Stockholm University, SE-106 91 Stockholm (Sweden); Asada, Hideo [Department of Dermatology, School of Medicine, Nara Medical University, 840 Shijo-cho, Kashihara, Nara 634-8521 (Japan); and others

    2011-01-07

    The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA{sup -/-}, FANCC{sup -/-}, FANCA{sup -/-}C{sup -/-}, FANCD2{sup -/-} and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical {gamma}H2AX-staining assay. Although the sensitivity of FANCA{sup -/-}, FANCC{sup -/-} and FANCA{sup -/-}C{sup -/-} cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2{sup -/-} cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, {gamma}H2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex. -- Research highlights: {yields} We examined to clarify the repair pathways of formaldehyde-induced DNA damage. Formaldehyde induces DNA double strand breaks (DSBs). {yields} DSBs are repaired through the Fanconi anemia (FA) repair pathway. {yields} This pathway is independent of the FA nuclear core complex. {yields} We also found that homologous recombination repair was induced by formaldehyde.

  11. Multistage 8.2 kyr event revealed through high-resolution XRF core scanning of Cuban sinkhole sediments

    Science.gov (United States)

    Peros, Matthew; Collins, Shawn; G'Meiner, Anna Agosta; Reinhardt, Eduard; Pupo, Felipe Matos

    2017-07-01

    We use sediments from a flooded sinkhole (Cenote Jennifer) in northern Cuba to provide new, well-dated, high-resolution evidence for the 8.2 kyr event. From 7600 to 8700 cal yr B.P. the sinkhole contained shallow, low-salinity water, which supported a marsh dominated by cattail and grass. Peaks in Cl and Br—occurring at 8150, 8200, and 8250 cal yr B.P.—are attributable to increased evaporation due to regional drying associated with the 8.2 kyr event. The three peaks in these elements also closely correspond to the greyscale record from the Cariaco Basin, indicative of increased upwelling in the southern Caribbean Sea at this time, supporting the notion of a multistage 8.2 kyr event. Our work provides new data that help to clarify the initiation, behavior, and impacts of the 8.2 kyr event in the northern tropics.

  12. Grain boundary sweeping and liquefaction-induced fission product behavior in nuclear fuel under severe-core damage accident conditions

    International Nuclear Information System (INIS)

    Rest, J.

    1984-05-01

    The theoretical FASTGRASS-VFP model has been used in the interpretation of fission gas, iodine, tellurium, and cesium release from: (1) irradiated high-burnup LWR fuel in a flowing steam atmosphere during high-temperature, in-cell heating tests performed at Oak Ridge National Laboratory; and (2) trace-irradiated and high-burnup LWR fuel during severe-fuel-damage (SFD) tests performed in the PBF reactor in Idaho. A theory of grain boundary sweeping of gas bubbles, gas bubble behavior during fuel liquefaction (destruction of grain boundaries due to formation of a U-rich melt phase), and U-Zr eutectic melting has been included within the FASTGRASS-VFP formalism. Results of the analyses demonstrate that intragranular fission product behavior during both types of tests can be interpreted in terms of a grain-growth/grain-boundary-sweeping mechanism that enhances the flow of fission products from within the grains to the grain boundaries. Whereas fuel liquefaction leads to an enhanced release of fission products in trace-irradiated fuel, the occurrence of fuel liquefaction in high-burnup fuel can degrade fission product release. This phenomenon is due in part to reduced gas-bubble mobilities in a viscous medium as compared to vapor transport, and in part to a degradation of grain growth rates and the subsequent decrease in grain-boundary sweeping of intragranular fission products into the liquefied lamina. The analysis shows that total UO 2 dissolution due to eutectic melting leads to increased release for both trace-irradiated and high-burnup fuel. The FASTGRASS-VFP predictions, measured release rates from the above tests, and previously published release rates are compared and differences between fission product behavior in trace-irradiated and in high-burnup fuel are highlighted

  13. Muscle Tissue Damage Induced by the Venom of Bothrops asper: Identification of Early and Late Pathological Events through Proteomic Analysis.

    Directory of Open Access Journals (Sweden)

    Cristina Herrera

    2016-04-01

    Full Text Available The time-course of the pathological effects induced by the venom of the snake Bothrops asper in muscle tissue was investigated by a combination of histology, proteomic analysis of exudates collected in the vicinity of damaged muscle, and immunodetection of extracellular matrix proteins in exudates. Proteomic assay of exudates has become an excellent new methodological tool to detect key biomarkers of tissue alterations for a more integrative perspective of snake venom-induced pathology. The time-course analysis of the intracellular proteins showed an early presence of cytosolic and mitochondrial proteins in exudates, while cytoskeletal proteins increased later on. This underscores the rapid cytotoxic effect of venom, especially in muscle fibers, due to the action of myotoxic phospholipases A2, followed by the action of proteinases in the cytoskeleton of damaged muscle fibers. Similarly, the early presence of basement membrane (BM and other extracellular matrix (ECM proteins in exudates reflects the rapid microvascular damage and hemorrhage induced by snake venom metalloproteinases. The presence of fragments of type IV collagen and perlecan one hour after envenoming suggests that hydrolysis of these mechanically/structurally-relevant BM components plays a key role in the genesis of hemorrhage. On the other hand, the increment of some ECM proteins in the exudate at later time intervals is likely a consequence of the action of endogenous matrix metalloproteinases (MMPs or of de novo synthesis of ECM proteins during tissue remodeling as part of the inflammatory reaction. Our results offer relevant insights for a more integrative and systematic understanding of the time-course dynamics of muscle tissue damage induced by B. asper venom and possibly other viperid venoms.

  14. Physical events that occur in the reactor core during load changes; Les effets physiques sur le coeur mis en jeu lors des variations de puissance

    Energy Technology Data Exchange (ETDEWEB)

    Paulin, Ph. [Electricite de France (EDF/DPN/UNIE/GECC), 93 - Saint-Denis (France); Golfier, H. [CEA Saclay (DEN-DANS/DM2S/SERMA/LPEC), 91 - Gif-sur-Yvette (France)

    2007-05-15

    The reactor core control aims at mastering 2 important parameters that are relevant for reactor availability and safety. First, the reactivity that sets the power output and secondly, the power map in order to handle hot spots. In PWR-type reactors, physical events such as moderator or fuel temperature changes, xenon concentration, that are important for both parameters, evolve during load changes but also during power plateaus and are dependent on burn-up. In this article temperature effect and xenon poisoning are analysed and their impact are assessed along an irradiation campaign through a core neutronic simulation and data from instrumentation. Xenon oscillations are particularly well illustrated. The counter-reactions of the means used for reactor controlling: soluble boron and control rods, are also analysed. (A.C.)

  15. Combining satellite imagery with forest inventory data to assess damage severity following a major blowdown event in northern Minnesota, USA

    Science.gov (United States)

    Mark D. Nelson; Sean P. Healey; W. Keith Moser; Mark H. Hansen

    2009-01-01

    Effects of a catastrophic blowdown event in northern Minnesota, USA were assessed using field inventory data, aerial sketch maps and satellite image data processed through the North American Forest Dynamics programme. Estimates were produced for forest area and net volume per unit area of live trees pre- and post-disturbance, and for changes in volume per unit area and...

  16. Building damage assessment after the earthquake in Haiti using two post-event satellite stereo imagery and DSMs

    DEFF Research Database (Denmark)

    Reinartz, Peter; Tian, Jiaojiao; Nielsen, Allan Aasbjerg

    2013-01-01

    In this paper, a novel disaster building damage monitoring method is presented. This method combines the multispectral imagery and DSMs from stereo matching to obtain three kinds of changes. The proposed method contains three basic steps. The first step is to segment the panchromatic images to ge...... (mainly temporary residential area, etc. tents). In the last step, a region based grey level co-occurrence matrix texture measurement is used to refine the third change class. The method is applied to building change detection after the Haiti earthquake....

  17. Dynamic event Tress applied to sequences Full Spectrum LOCA. Calculating the frequency of excedeence of damage by integrated Safety Analysis Methodology

    International Nuclear Information System (INIS)

    Gomez-Magan, J. J.; Fernandez, I.; Gil, J.; Marrao, H.; Queral, C.; Gonzalez-Cadelo, J.; Montero-Mayorga, J.; Rivas, J.; Ibane-Llano, C.; Izquierdo, J. M.; Sanchez-Perea, M.; Melendez, E.; Hortal, J.

    2013-01-01

    The Integrated Safety Analysis (ISA) methodology, developed by the Spanish Nuclear Safety council (CSN), has been applied to obtain the dynamic Event Trees (DETs) for full spectrum Loss of Coolant Accidents (LOCAs) of a Westinghouse 3-loop PWR plant. The purpose of this ISA application is to obtain the Damage Excedence Frequency (DEF) for the LOCA Event Tree by taking into account the uncertainties in the break area and the operator actuation time needed to cool down and de pressurize reactor coolant system by means of steam generator. Simulations are performed with SCAIS, a software tool which includes a dynamic coupling with MAAP thermal hydraulic code. The results show the capability of the ISA methodology to obtain the DEF taking into account the time uncertainty in human actions. (Author)

  18. Using an extended 2D hydrodynamic model for evaluating damage risk caused by extreme rain events: Flash-Flood-Risk-Map (FFRM) Upper Austria

    Science.gov (United States)

    Humer, Günter; Reithofer, Andreas

    2016-04-01

    Using an extended 2D hydrodynamic model for evaluating damage risk caused by extreme rain events: Flash-Flood-Risk-Map (FFRM) Upper Austria Considering the increase in flash flood events causing massive damage during the last years in urban but also rural areas [1-4], the requirement for hydrodynamic calculation of flash flood prone areas and possible countermeasures has arisen to many municipalities and local governments. Besides the German based URBAS project [1], also the EU-funded FP7 research project "SWITCH-ON" [5] addresses the damage risk caused by flash floods in the sub-project "FFRM" (Flash Flood Risk Map Upper Austria) by calculating damage risk for buildings and vulnerable infrastructure like schools and hospitals caused by flash-flood driven inundation. While danger zones in riverine flooding are established as an integral part of spatial planning, flash floods caused by overland runoff from extreme rain events have been for long an underrated safety hazard not only for buildings and infrastructure, but man and animals as well. Based on the widespread 2D-model "hydro_as-2D", an extension was developed, which calculates the runoff formation from a spatially and temporally variable precipitation and determines two dimensionally the land surface area runoff and its concentration. The conception of the model is to preprocess the precipitation data and calculate the effective runoff-volume for a short time step of e.g. five minutes. This volume is applied to the nodes of the 2D-model and the calculation of the hydrodynamic model is started. At the end of each time step, the model run is stopped, the preprocessing step is repeated and the hydraulic model calculation is continued. In view of the later use for the whole of Upper Austria (12.000 km²) a model grid of 25x25 m² was established using digital elevation data. Model parameters could be estimated for the small catchment of river Ach, which was hit by an intense rain event with up to 109 mm per hour

  19. Studies of DNA repair in Saccharomyces cerevisiae. I. Characterization of a new allele of RAD6. II. Investigation of events in the first cell cycle after DNA damage

    International Nuclear Information System (INIS)

    Dolthwright-Fasse, J.A.

    1980-01-01

    Studies in two independent, but related, areas of DNA repair have been carried out in the eucaryotic yeast, Saccharomyces cerevisiae. The first is the characterization of a new allele in the RAD6 gene suggesting that the gene is multifunctional. The second is the utilization of photoreactivation as a probe of events occurring during the first cell cycle after DNA damage. Strains carrying the new allele, designated rad6-4, of the RAD6 locus are about as sensitive to uv and ionizing radiation as those carrying rad6-1 or rad6-3. Although rad6-4 may well be a missense mutation, the data suggest that the RAD6 gene is multifunctional. One function is necessary to recover from DNA damage in an error-free manner, and the other is concerned with mutagenic processes and sporulation. The loss of photoreversibility (LOP) of ultraviolet induced mutations to arginine independence in an excision defective strain carrying arg4-17 examines the events occurring in the first cell cycle. The post uv protein synthesis causes pyrimidine dimmers to become inaccessible to the photoreactivating enzyme in some unknown manner. There is no evidence indicating whether the normal function of the protein is involved in excision repair, or in one of the two repair processes believed to be inducible; induced mutagenesis or recombinational repair

  20. Ultraviolet radiation-induced interleukin 6 release in HeLa cells is mediated via membrane events in a DNA damage-independent way.

    Science.gov (United States)

    Kulms, D; Pöppelmann, B; Schwarz, T

    2000-05-19

    Evidence exists that ultraviolet radiation (UV) affects molecular targets in the nucleus or at the cell membrane. UV-induced apoptosis was found to be mediated via DNA damage and activation of death receptors, suggesting that nuclear and membrane effects are not mutually exclusive. To determine whether participation of nuclear and membrane components is also essential for other UV responses, we studied the induction of interleukin-6 (IL-6) by UV. Exposing HeLa cells to UV at 4 degrees C, which inhibits activation of surface receptors, almost completely prevented IL-6 release. Enhanced repair of UV-mediated DNA damage by addition of the DNA repair enzyme photolyase did not affect UV-induced IL-6 production, suggesting that in this case membrane events predominant over nuclear effects. UV-induced IL-6 release is mediated via NFkappaB since the NFkappaB inhibitor MG132 or transfection of cells with a super-repressor form of the NFkappaB inhibitor IkappaB reduced IL-6 release. Transfection with a dominant negative mutant of the signaling protein TRAF-2 reduced IL-6 release upon exposure to UV, indicating that UV-induced IL-6 release is mediated by activation of the tumor necrosis factor receptor-1. These data demonstrate that UV can exert biological effects mainly by affecting cell surface receptors and that this is independent of its ability to induce nuclear DNA damage.

  1. Neutron Fluence, Dosimetry and Damage Response Determination in In-Core/Ex-Core Components of the VENUS CEN/SCK LWR Using 3-D Monte Carlo Simulations: NEA's VENUS-3 Benchmark

    International Nuclear Information System (INIS)

    Perlado, J. Manuel; Marian, Jaime; Sanz, Jesus Garcia

    2000-01-01

    Validating state-of-the-art methods used to predict fluence exposure to reactor pressure vessels (RPVs) has become an important issue in identifying the sources of uncertainty in the estimated RPV fluence for pressurized water reactors. This is a very important aspect in evaluating irradiation damage leading to the hardening and embrittlement of such structural components. One of the major benchmark experiments carried out to test three-dimensional methodologies is the VENUS-3 Benchmark Experiment in which three-dimensional Monte Carlo and S n codes have proved more efficient than synthesis methods. At the Instituto de Fusion Nuclear (DENIM) at the Universidad Politecnica de Madrid, a detailed full three-dimensional model of the Venus Critical Facility has been developed making use of the Monte Carlo transport code MCNP4B. The problem geometry and source modeling are described, and results, including calculated versus experimental (C/E) ratios as well as additional studies, are presented. Evidence was found that the great majority of C/E values fell within the 10% tolerance and most within 5%. Tolerance limits are discussed on the basis of evaluated data library and fission spectra sensitivity, where a value ranging between 10 to 15% should be accepted. Also, a calculation of the atomic displacement rate has been carried out in various locations throughout the reactor, finding that values of 0.0001 displacements per atom in external components such as the core barrel are representative of this type of reactor during a 30-yr time span

  2. Development and Evaluation of Vectorised and Multi-Core Event Reconstruction Algorithms within the CMS Software Framework

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    The processing of data acquired by the CMS detector at LHC is carried out with an object-oriented C++ software framework: CMSSW. With the increasing luminosity delivered by the LHC, the treatment of recorded data requires extraordinary large computing resources, also in terms of CPU usage. A possible solution to cope with this task is the exploitation of the features offered by the latest microprocessor architectures. Modern CPUs present several vector units, the capacity of which is growing steadily with the introduction of new processor generations. Moreover, an increasing number of cores per die is offered by the main vendors, even on consumer hardware. Most recent C++ compilers provide facilities to take advantage of such innovations, either by explicit statements in the programs’ sources or automatically adapting the generated machine instructions to the available hardware, without the need of modifying the existing code base. Programming techniques to implement reconstruction algorithms and optimised ...

  3. Studies of DNA repair in saccharomyces cerevisiae. I. Characterization of a new allele of RAD6. II. Investigation of events in the first cell cycle after DNA damage

    International Nuclear Information System (INIS)

    Douthwright-Fasse, J.A.

    1979-01-01

    Studies in two independent, but related, areas of DNA repair have been carried out in Saccharomyces cerevisiae; characterization of a new allele in the RAD6 gene which suggests that the gene is multifunctional, and utilization of photoreactivation as a probe of events occurring during the first cell cycle after DNA damage. Strains carrying the new allele, designated rad6-4, are as sensitive to uv and ionizing radiation as those carrying rad6-1 or rad6-3 but, unlike them, are capable of induced mutagenesis and sporulation. Although rad6-4 may well be a missense mutation, the evidence shows that it is unlikely that this phenotype is due to leakiness. Instead, the data suggest that the RAD6 gene is multifunctional. One function is necessary to recover from DNA damage in an error-free manner, and the other is concerned with mutagenic processes and sporulation. Rad6-1 and rad6-3 strains are deficient in both of these functions, while rad6-4 strains are deficient only in the error-free function. The loss of photoreversibility (LOP) of ultraviolet induced mutations to arginine independence in an excision defective strain carrying arg4-17 examines the events occurring in the first cell cycle after DNA damage. LOP is dependent upon de novo protein synthesis. LOP begins immediately after UV irradiation, before semiconservative DNA synthesis takes place, and is complete after four hours in growth medium.There is no evidence indicating whether the normal function of the protein is involved in excision repair, or in one of the two repair processes believed to be inducible; induced mutagenesis or recombinational repair

  4. No post-no core approach to restore severely damaged posterior teeth: An up to 10-year retrospective study of documented endocrown cases.

    Science.gov (United States)

    Belleflamme, Marcia M; Geerts, Sabine O; Louwette, Marie M; Grenade, Charlotte F; Vanheusden, Alain J; Mainjot, Amélie K

    2017-08-01

    The objectives of the present study were to (1) retrospectively evaluate documented cases of ceramic and composite endocrowns performed using immediate dentin sealing (IDS); (2) correlate failures with clinical parameters such as tooth preparation characteristics and occlusal parameters. 99 documented cases of endocrowns were evaluated after a mean observation period of 44.7±34.6months. A classification of restorations was established in function of the level of damage of residual tooth tissues after preparation, from 1 to 3. Evaluation was performed according to FDI criteria and endodontic outcomes were analyzed. Occlusal risk factors were examined and fractographic analysis was performed in case of fracture. 48.4% of patients were shown to present occlusal risk factors. 75.8% of restorations were Class 3 endocrowns. 56.6% were performed on molars, 41.4% on premolars and 2.0% on canines. 84.8% were performed in lithium-disilicate glass-ceramic and 12.1% in Polymer-Infiltrated Ceramic Network (PICN) material. The survival and success rates of endocrowns were 99.0% and 89.9% respectively, while the 10-year Kaplan-Meier estimated survival and success rates were 98.8% and 54.9% respectively. Ten failures were detected: periodontal disease (n=3), endocrown debonding (n=2), minor chipping (n=2), caries recurrence (n=2) and major fractures (n=1). Due to the reduced amount of failures, no statistical correlation could be established with clinical parameters. Endocrowns were shown to constitute a reliable approach to restore severely damaged molars and premolars, even in the presence of extensive coronal tissue loss or occlusal risk factors, such as bruxism or unfavorable occlusal relationships. Practitioners should consider the endocrown instead of the post and core approach to restore severely damaged non-vital posterior teeth. This minimally invasive solution reduces the risk of catastrophic failures and is easily performed. The use of IDS procedure and lithium

  5. Record-low primary productivity and high plant damage in the Nordic Arctic Region in 2012 caused by multiple weather events and pest outbreaks

    International Nuclear Information System (INIS)

    Bjerke, Jarle W; Jepsen, Jane U; Lovibond, Sarah; Tømmervik, Hans; Rune Karlsen, Stein; Arild Høgda, Kjell; Malnes, Eirik; Vikhamar-Schuler, Dagrun

    2014-01-01

    The release of cold temperature constraints on photosynthesis has led to increased productivity (greening) in significant parts (32–39%) of the Arctic, but much of the Arctic shows stable (57–64%) or reduced productivity (browning, <4%). Summer drought and wildfires are the best-documented drivers causing browning of continental areas, but factors dampening the greening effect of more maritime regions have remained elusive. Here we show how multiple anomalous weather events severely affected the terrestrial productivity during one water year (October 2011–September 2012) in a maritime region north of the Arctic Circle, the Nordic Arctic Region, and contributed to the lowest mean vegetation greenness (normalized difference vegetation index) recorded this century. Procedures for field data sampling were designed during or shortly after the events in order to assess both the variability in effects and the maximum effects of the stressors. Outbreaks of insect and fungal pests also contributed to low greenness. Vegetation greenness in 2012 was 6.8% lower than the 2000–11 average and 58% lower in the worst affected areas that were under multiple stressors. These results indicate the importance of events (some being mostly neglected in climate change effect studies and monitoring) for primary productivity in a high-latitude maritime region, and highlight the importance of monitoring plant damage in the field and including frequencies of stress events in models of carbon economy and ecosystem change in the Arctic. Fourteen weather events and anomalies and 32 hypothesized impacts on plant productivity are summarized as an aid for directing future research. (letter)

  6. Can the critical temperature for photochemical damage in common bean plants be changed after a drought event?

    Directory of Open Access Journals (Sweden)

    Rafael Vasconcelos Ribeiro

    2015-08-01

    Full Text Available Low water availability and high temperatures occur under field conditions and we hypothesize that the critical temperature for photochemical damage (TC in common bean (Phaseolus vulgaris L. plants is increased by the occurrence of previous water deficit in a genotype-dependent manner. Five common bean cultivars A320, A222, Carioca, BAT477 and Ouro Negro were evaluated. Thirty days after seedlings emergence, one group of plants was exposed to water deficit for ten days and rehydrated and another one was maintained well hydrated during the experimental period. The minimum chlorophyll fluorescence (FO was monitored in leaf discs exposed to temperatures ranging from 25 to 45 oC and the TC values estimated. The previous water deficit did not affect TC, which varied between 38.8 and 43.8 oC when considering all cultivars and water regimes. Under well-watered conditions, BAT477 (41.9 oC and Carioca (43.8 oC presented higher TCthan Ouro Negro (38.8 oC. Our findings indicate a significant genotypic variation in thermal tolerance in Phaseolus vulgaris, an important crop trait to be considered in breeding programs.

  7. The OECD/NEA workshop on the indemnification of nuclear damage in the event of a nuclear accident

    International Nuclear Information System (INIS)

    Wagstaff, F.

    2002-01-01

    Since 1993, the OECD Nuclear Energy Agency (OECD/NEA) has run the International Nuclear Emergency Exercise (INEX) Program. The program serves to discuss an effective accident management approach on the basis of a simulated nuclear accident situation together with the states involved and their institutions, and also elaborate measures for its further improvement. At the present time, the INEX Program has reached Phase 3 in which, for the first time, also aspects of liability for the consequences of accidents were included. These aspects were made the subject of a workshop held after an emergency exercise. The scenario covered was based on an INES level-4 accident in the French Gravelines Nuclear Power Station situated close to the French-Belgian border. The workshop dealt with these topics, among others: the application of the Paris Convention on Third Party Liability, the Brussels Supplementary Convention, and the Vienna Convention on Civil Liability for Nuclear Damage as well as the Supplementary Compensation Convention of 1997. It was seen that there was a clear need for further discussion, especially to shed more light on the interrelationship of these treaties. (orig.) [de

  8. Development and Evaluation of Vectorised and Multi-Core Event Reconstruction Algorithms within the CMS Software Framework

    Science.gov (United States)

    Hauth, T.; Innocente and, V.; Piparo, D.

    2012-12-01

    The processing of data acquired by the CMS detector at LHC is carried out with an object-oriented C++ software framework: CMSSW. With the increasing luminosity delivered by the LHC, the treatment of recorded data requires extraordinary large computing resources, also in terms of CPU usage. A possible solution to cope with this task is the exploitation of the features offered by the latest microprocessor architectures. Modern CPUs present several vector units, the capacity of which is growing steadily with the introduction of new processor generations. Moreover, an increasing number of cores per die is offered by the main vendors, even on consumer hardware. Most recent C++ compilers provide facilities to take advantage of such innovations, either by explicit statements in the programs sources or automatically adapting the generated machine instructions to the available hardware, without the need of modifying the existing code base. Programming techniques to implement reconstruction algorithms and optimised data structures are presented, that aim to scalable vectorization and parallelization of the calculations. One of their features is the usage of new language features of the C++11 standard. Portions of the CMSSW framework are illustrated which have been found to be especially profitable for the application of vectorization and multi-threading techniques. Specific utility components have been developed to help vectorization and parallelization. They can easily become part of a larger common library. To conclude, careful measurements are described, which show the execution speedups achieved via vectorised and multi-threaded code in the context of CMSSW.

  9. Analysis of the danger potential of H2/CO-combustion in the event of core meltdown

    International Nuclear Information System (INIS)

    Fischer, M.; Wagler, K.; Schwarzott, W.; Reineke, H.H.

    1987-01-01

    Based on an evaluation of the present state of knowledge and the experiments performed, several computing programs for the simulation of H 2 /CO combustion processes were developed within the scope of this project. Besides the one-compartment-model MOPED, based on the formulation of empirical and phenomenological connections, which was also used later to perform the pressure buildup analyses during various core meltdown (CM) scenarios, these were the first two attempts in respect of a fluid-dynamic description of the combustion processes that also takes the reaction kinetics into account (VERLA code, PISCES code). The analysis of the low (LP) and high (HP) pressure path CM conditions showed that no additional risk arises on the HP path due to potential H 2 combustion. In opposition to this maximum combustion gas fractions of 15% by vol. H 2 and 2.5% by vol. CO with assumption of complete enrichment in the containment result on the LP path. With 37 refs., 3 tabs., 78 figs [de

  10. Visualisation of γH2AX Foci Caused by Heavy Ion Particle Traversal; Distinction between Core Track versus Non-Track Damage

    Science.gov (United States)

    Nakajima, Nakako Izumi; Brunton, Holly; Watanabe, Ritsuko; Shrikhande, Amruta; Hirayama, Ryoichi; Matsufuji, Naruhiro; Fujimori, Akira; Murakami, Takeshi; Okayasu, Ryuichi; Jeggo, Penny; Shibata, Atsushi

    2013-01-01

    Heavy particle irradiation produces complex DNA double strand breaks (DSBs) which can arise from primary ionisation events within the particle trajectory. Additionally, secondary electrons, termed delta-electrons, which have a range of distributions can create low linear energy transfer (LET) damage within but also distant from the track. DNA damage by delta-electrons distant from the track has not previously been carefully characterised. Using imaging with deconvolution, we show that at 8 hours after exposure to Fe (∼200 keV/µm) ions, γH2AX foci forming at DSBs within the particle track are large and encompass multiple smaller and closely localised foci, which we designate as clustered γH2AX foci. These foci are repaired with slow kinetics by DNA non-homologous end-joining (NHEJ) in G1 phase with the magnitude of complexity diminishing with time. These clustered foci (containing 10 or more individual foci) represent a signature of DSBs caused by high LET heavy particle radiation. We also identified simple γH2AX foci distant from the track, which resemble those arising after X-ray exposure, which we attribute to low LET delta-electron induced DSBs. They are rapidly repaired by NHEJ. Clustered γH2AX foci induced by heavy particle radiation cause prolonged checkpoint arrest compared to simple γH2AX foci following X-irradiation. However, mitotic entry was observed when ∼10 clustered foci remain. Thus, cells can progress into mitosis with multiple clusters of DSBs following the traversal of a heavy particle. PMID:23967070

  11. Coolability of severely degraded CANDU cores

    International Nuclear Information System (INIS)

    Meneley, D.A.; Blahnik, C.; Rogers, J.T.; Snell, V.G.; Mijhawan, S.

    1995-07-01

    Analytical and experimental studies have shown that the separately cooled moderator in a CANDU reactor provides an effective heat sink in the event of a loss-of-coolant accident (LOCA) accompanied by total failure of the emergency core cooling system (ECCS). The moderator heat sink prevents fuel melting and maintains the integrity of the fuel channels, therefore terminating this severe accident short of severe core damage. Nevertheless, there is a probability, however low, that the moderator heat sink could fail in such an accident. The pioneering work of Rogers (1984) for such a severe accident using simplified models showed that the fuel channels would fail and a bed of dry, solid debris would be formed at the bottom of the calandria which would heat up and eventually melt. However, the molten pool of core material would be retained in the calandria vessel, cooled by the independently cooled shield-tank water, and would eventually re solidify. Thus, the calandria vessel would act inherently as a core-catcher as long as the shield tank integrity is maintained. The present paper reviews subsequent work on the damage to a CANDU core under severe accident conditions and describes an empirically based mechanistic model of this process. It is shown that, for such severe accident sequences in a CANDU reactor, the end state following core disassembly consists of a porous bed of dry solid, coarse debris, irrespective of the initiating event and the core disassembly process. (author). 48 refs., 3 tabs., 18 figs

  12. Coolability of severely degraded CANDU cores. Revised

    International Nuclear Information System (INIS)

    Meneley, D.A.; Blahnik, C.; Rogers, J.T.; Snell, V.G.; Nijhawan, S.

    1996-01-01

    Analytical and experimental studies have shown that the separately cooled moderator in a CANDU reactor provides an effective heat sink in the event of a loss-of-coolant accident (LOCA) accompanied by total failure of the emergency core cooling system (ECCS). The moderator heat sink prevents fuel melting and maintains the integrity of the fuel channels, therefore terminating this severe accident short of severe core damage. Nevertheless, there is a probability, however low, that the moderator heat sink could fail in such an accident. The pioneering work of Rogers (1984) for such a severe accident using simplified models showed that the fuel channels would fail and a bed of dry, solid debris would be formed at the bottom of the calandria which would heat up and eventually melt. However, the molten pool of core material would be retained in the calandria vessel, cooled by the independently cooled shield-tank water, and would eventually resolidify. Thus, the calandria vessel would act inherently as a 'core-catcher' as long as the shield tank integrity is maintained. The present paper reviews subsequent work on the damage to a CANDU core under severe accident conditions and describes an empirically based mechanistic model of this process. It is shown that, for such severe accident sequences in a CANDU reactor, the end state following core disassembly consists of a porous bed of dry solid, coarse debris, irrespective of the initiating event and the core disassembly process. (author)

  13. Predation by feeding aggregations of Drupella spp. inhibits the recovery of reefs damaged by a mass bleaching event

    Science.gov (United States)

    Bruckner, Andrew W.; Coward, Georgia; Bimson, Kathyrn; Rattanawongwan, Tipwimon

    2017-12-01

    High densities of two corallivorous gastropods, Drupella cornus and D. rugosa, may delay the recovery of coral reefs impacted by mass bleaching events by aggregating on the remaining corals. Following severe bleaching in April/May 2016 that resulted in the loss of up to 80% of the living coral cover from reefs in South Malé, Maldives, aggregations of up to 250 Drupella per coral were recorded on surviving colonies. The distribution of snails was not random; larger aggregations were seen on reefs with fewer remaining live corals and also on the largest corals. Branching, digitate and tabular corals, especially species of Acropora and Pocillopora, sustained the highest mortality from the bleaching. Remaining colonies of these taxa exhibited the highest occurrence of snails and the most extensive snail predation, although less-preferred taxa such as Montipora, Porites, Astreopora, Cyphastrea and Pachyseris were also targeted. Drupella also concentrated on broken Acropora branches and overturned colonies; on some reefs, these were the only surviving acroporids, and many of them did not bleach. Continued predation pressure from Drupella may eliminate formerly dominant corals, including genets that are resistant to higher sea water temperatures.

  14. Experimental study of divertor plasma-facing components damage under a combination of pulsed and quasi-stationary heat loads relevant to expected transient events at ITER

    International Nuclear Information System (INIS)

    Klimov, N S; Podkovyrov, V L; Kovalenko, D V; Zhitlukhin, A M; Barsuk, V A; Mazul, I V; Giniyatulin, R N; Kuznetsov, V Ye; Riccardi, B; Loarte, A; Merola, M; Koidan, V S; Linke, J; Landman, I S; Pestchanyi, S E; Bazylev, B N

    2011-01-01

    This paper concerns the experimental study of damage of ITER divertor plasma-facing components (PFCs) under a combination of pulsed plasma heat loads (representative of controlled ITER type I edge-localized modes (ELMs)) and quasi-stationary heat loads (representative of the high heat flux (HHF) thermal fatigue expected during ITER normal operations and slow transient events). The PFC's tungsten armor damage under pulsed plasma exposure was driven by (i) the melt layer motion, which leads to bridges formation between neighboring tiles and (ii) the W brittle failure giving rise to a stable crack pattern on the exposed surface. The crack width reaches a saturation value that does not exceed some tens of micrometers after several hundreds of ELM-like pulses. HHF thermal fatigue tests have shown (i) a peeling-off of the re-solidified material due to its brittle failure and (ii) a significant widening (up to 10 times) of the cracks and the formation of additional cracks.

  15. Building Damage and Business Continuity Management in the Event of Natural Hazards: Case Study of the 2004 Tsunami in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Masami Sugiura

    2013-01-01

    Full Text Available The Sumatra Earthquake and Indian Ocean Tsunami event on the 26 December 2004 has provided a unique and valuable opportunity to evaluate the performance of various structures, facilities and lifeline systems during the tsunami wave attacks. There are especially meaningful observations concerning the structural changes due to the tsunami forces, which open up a wide area of research to develop the mitigation procedure. The business restoration process of business companies in terms of buildings, facilities and lifelines have shown greater research interest. In this study, we investigated the restoration process of business sectors in East and South coastal region in Sri Lanka after the 2004 Indian Ocean Tsunami. A field survey was conducted in East and South coast of Sri Lanka, in order to study the affecting parameters to damage assessment in the restoration process of the business companies. The results of the questionnaire-based field survey are then compared with the statistical analysis results. Finally, the factors affecting the restoration process after the tsunami are identified. As a main conclusion, financial support could be the most important reason for delays in restoration. Moreover, it has been observed that the tsunami inundation level of higher than one meter may have had more effect concerning the damage to the structures and requires additional time for restoration than other areas.

  16. Radiation damage prediction system using damage function

    International Nuclear Information System (INIS)

    Tanaka, Yoshihisa; Mori, Seiji

    1979-01-01

    The irradiation damage analysis system using a damage function was investigated. This irradiation damage analysis system consists of the following three processes, the unfolding of a damage function, the calculation of the neutron flux spectrum of the object of damage analysis and the estimation of irradiation effect of the object of damage analysis. The damage function is calculated by applying the SAND-2 code. The ANISN and DOT3, 5 codes are used to calculate neutron flux. The neutron radiation and the allowable time of reactor operation can be estimated based on these calculations of the damage function and neutron flux. The flow diagram of the process of analyzing irradiation damage by a damage function and the flow diagram of SAND-2 code are presented, and the analytical code for estimating damage, which is determined with a damage function and a neutron spectrum, is explained. The application of the irradiation damage analysis system using a damage function was carried out to the core support structure of a fast breeder reactor for the damage estimation and the uncertainty evaluation. The fundamental analytical conditions and the analytical model for this work are presented, then the irradiation data for SUS304, the initial estimated values of a damage function, the error analysis for a damage function and the analytical results are explained concerning the computation of a damage function for 10% total elongation. Concerning the damage estimation of FBR core support structure, the standard and lower limiting values of damage, the permissible neutron flux and the allowable years of reactor operation are presented and were evaluated. (Nakai, Y.)

  17. Caenorhabditis elegans as an alternative in vivo model to determine oral uptake, nanotoxicity, and efficacy of melatonin-loaded lipid-core nanocapsules on paraquat damage.

    Science.gov (United States)

    Charão, Mariele Feiffer; Souto, Caroline; Brucker, Natália; Barth, Anelise; Jornada, Denise S; Fagundez, Daiandra; Ávila, Daiana Silva; Eifler-Lima, Vera L; Guterres, Silvia S; Pohlmann, Adriana R; Garcia, Solange Cristina

    2015-01-01

    Caenorhabditis elegans is an alternative in vivo model that is being successfully used to assess the pharmacological and toxic effects of drugs. The exponential growth of nanotechnology requires the use of alternative in vivo models to assess the toxic effects of theses nanomaterials. The use of polymeric nanocapsules has shown promising results for drug delivery. Moreover, these formulations have not been used in cases of intoxication, such as in treatment of paraquat (PQ) poisoning. Thus, the use of drugs with properties improved by nanotechnology is a promising approach to overcome the toxic effects of PQ. This research aimed to evaluate the absorption of rhodamine B-labeled melatonin (Mel)-loaded lipid-core nanocapsules (LNC) by C. elegans, the application of this model in nanotoxicology, and the protection of Mel-LNC against PQ damage. The formulations were prepared by self-assembly and characterized by particle sizing, zeta potential, drug content, and encapsulation efficiency. The results demonstrated that the formulations had narrow size distributions. Rhodamine B-labeled Mel-LNC were orally absorbed and distributed in the worms. The toxicity assessment of LNC showed a lethal dose 50% near the highest dose tested, indicating low toxicity of the nanocapsules. Moreover, pretreatment with Mel-LNC significantly increased the survival rate, reduced the reactive oxygen species, and maintained the development in C. elegans exposed to PQ compared to those worms that were either untreated or pretreated with free Mel. These results demonstrated for the first time the uptake and distribution of Mel-LNC by a nematode, and indicate that while LNC is not toxic, Mel-LNC prevents the effects of PQ poisoning. Thus, C. elegans may be an interesting alternative model to test the nanocapsules toxicity and efficacy.

  18. Managing water addition to a degraded core

    International Nuclear Information System (INIS)

    Kuan, P.; Hanson, D.J.; Odar, F.

    1992-01-01

    In this paper the authors present information that can be used in severe accident management by providing an improved understanding of the effects of water addition to a degraded core. This improved understanding is developed using a diagram showing a sequence of core damage states. Whenever possible, a temperature and a time after accident initiation are estimated for each damage state in the sequence diagram. This diagram can be used to anticipate the evolution of events during an accident. Possible responses of plant instruments are described to identify these damage states and the effects of water addition. The rate and amount of water addition needed (a) to remove energy from the core, (b) to stabilize the core or (c) to not adversely affect the damage progression, are estimated. Analysis of the capability to remove energy from large cohesive and particulate debris beds indicates that these beds may not be stabilized in the core region and they may partially relocate to the lower plenum of the reactor vessel

  19. Precursors to potential severe core damage accidents: 1992, a status report; Volume 18: Appendices B, C, D, E, F, and G

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1993-12-01

    This document is part of a report which documents 1992 operational events selected as accident sequence precursors. This report describes the 27 precursors identified from the 1992 licensee event reports. It also describe containment-related events; {open_quote}interesting{close_quote} events; potentially significant events that were considered impractical to analyze; copies of the licensee event reports which were cited in the cases above; and comments from the licensee and NRC in response to the preliminary reports.

  20. Dust Deposition Events on Mt. Elbrus, Caucasus Mountains in the 21st Century Reconstructed from the Shallow Firn and Ice Cores (Invited)

    Science.gov (United States)

    Shahgedanova, M.; Kutuzov, S.; Mikhalenko, V.; Ginot, P.; Lavrentiev, I.

    2013-12-01

    This paper presents and discusses a record of dust deposition events reconstructed from the shallow firn and ice cores extracted on the Western Plateau, Mt. Elbrus, Caucasus Mountains, Russia. A combination of SEVIRI imagery, HYSPLIT trajectory model, meteorological and atmospheric optical depth data were used to establish timing of deposition events and source regions of dust with very high temporal (hours) and spatial (c. 50-100 km) resolution. The source regions of the desert dust transported to Mt. Elbrus were primarily located in the Middle East, in particular in eastern Syria and in the Syrian Desert at the border between Saudi Arabia, Iraq and Jordan. Northern Sahara, the foothills of the Djebel Akhdar Mountains in eastern Libya and the border region between Libya and Algeria were other important sources of desert dust. Dust sources in the Sahara were natural (e.g. palaeolakes and alluvial deposits in the foothills) while in the Middle East, dust entrainment occurred from both natural (e.g. dry river beds) and anthropogenic (e.g. agricultural fields) sources. The overall majority of dust deposition events occurred between March and June and, less frequently, dust deposition events occurred in February and October. In all cases, dust deposition was associated with depressions causing strong surface wind and dust uplift in the source areas, transportation of dust to the Caucasus with a strong south-westerly flow from the Sahara or southerly flow from the Middle East, merging of the dust clouds with precipitation-bearing weather fronts and precipitation over the Caucasus region. The Saharan depressions were vigorous and associated with stronger daily wind speeds of 20-30 m/s at the 700 hPa level; depressions forming over the Middle East and the associated wind speeds were weaker at 12-15 m/s. The Saharan depressions were less frequent than those carrying dust from the Middle East but higher dust loads were associated with the Saharan depressions. A higher

  1. Trending analysis of precursor events

    International Nuclear Information System (INIS)

    Watanabe, Norio

    1998-01-01

    The Accident Sequence Precursor (ASP) Program of United States Nuclear Regulatory Commission (U.S.NRC) identifies and categorizes operational events at nuclear power plants in terms of the potential for core damage. The ASP analysis has been performed on yearly basis and the results have been published in the annual reports. This paper describes the trends in initiating events and dominant sequences for 459 precursors identified in the ASP Program during the 1969-94 period and also discusses a comparison with dominant sequences predicted in the past Probabilistic Risk Assessment (PRA) studies. These trends were examined for three time periods, 1969-81, 1984-87 and 1988-94. Although the different models had been used in the ASP analyses for these three periods, the distribution of precursors by dominant sequences show similar trends to each other. For example, the sequences involving loss of both main and auxiliary feedwater were identified in many PWR events and those involving loss of both high and low coolant injection were found in many BWR events. Also, it was found that these dominant sequences were comparable to those determined to be dominant in the predictions by the past PRAs. As well, a list of the 459 precursors identified are provided in Appendix, indicating initiating event types, unavailable systems, dominant sequences, conditional core damage probabilities, and so on. (author)

  2. Core component integration tests for the back-end software sub-system in the ATLAS data acquisition and event filter prototype -1 project

    International Nuclear Information System (INIS)

    Badescu, E.; Caprini, M.; Niculescu, M.; Radu, A.

    2000-01-01

    The ATLAS data acquisition (DAQ) and Event Filter (EF) prototype -1 project was intended to produce a prototype system for evaluating candidate technologies and architectures for the final ATLAS DAQ system on the LHC accelerator at CERN. Within the prototype project, the back-end sub-system encompasses the software for configuring, controlling and monitoring the DAQ. The back-end sub-system includes core components and detector integration components. The core components provide the basic functionality and had priority in terms of time-scale for development in order to have a baseline sub-system that can be used for integration with the data-flow sub-system and event filter. The following components are considered to be the core of the back-end sub-system: - Configuration databases, describe a large number of parameters of the DAQ system architecture, hardware and software components, running modes and status; - Message reporting system (MRS), allows all software components to report messages to other components in the distributed environment; - Information service (IS) allows the information exchange for software components; - Process manager (PMG), performs basic job control of software components (start, stop, monitoring the status); - Run control (RC), controls the data taking activities by coordinating the operations of the DAQ sub-systems, back-end software and external systems. Performance and scalability tests have been made for individual components. The back-end subsystem integration tests bring together all the core components and several trigger/DAQ/detector integration components to simulate the control and configuration of data taking sessions. For back-end integration tests a test plan was provided. The tests have been done using a shell script that goes through different phases as follows: - starting the back-end server processes to initialize communication services and PMG; - launching configuration specific processes via DAQ supervisor as

  3. Risk of nuclear damage

    International Nuclear Information System (INIS)

    Kienzl, K.

    1997-01-01

    Following the opening and words of welcome by Mr. Fritz Unterpertinger (unit director at the Austrian Federal Ministry for the Environment, Youth and Family; BMUJF) Mrs Helga Kromp-Kolb (professor at the Institute for Meteorology and Physics of the University of Natural Resources Science Vienna) illustrated the risks of nuclear damage in Europe by means of a nuclear risk map. She explained that even from a scientific or technical point of view the assessment of risks arising from nuclear power stations was fraught with great uncertainties. Estimates about in how far MCAs (maximum credible accident) could still be controlled by safety systems vary widely and so do assessments of the probability of a core melt. But there is wide agreement in all risk assessments conducted so far that MCAs might occur within a - from a human point of view - conceivable number of years. In this connection one has to bear in mind that the occurrence of such a major accident - whatever its probability may be - could entail immense damage and the question arises whether or not it is at all justifiable to expose the general public to such a risk. Klaus Rennings (Centre for European Economic Research, Mannheim, Germany) dealt with the economic aspects of nuclear risk assessment. He explained that there are already a number of studies available aiming to assess the risk of damage resulting from a core melt accident in economic terms. As to the probability of occurrence estimates vary widely between one incident in 3,333 and 250,000 year of reactor operation. It is assumed, however, that a nuclear accident involving a core melt in Germany would probably exceed the damage caused by the Chernobyl accident. The following speakers addressed the legal aspects of risks associated with nuclear installations. Mrs Monika Gimpel-Hinteregger (professor at the Institute for Civil Law in Graz) gave an overview on the applicable Austrian law concerning third party liability in the field of nuclear energy

  4. Iceberg and meltwater discharge events in the western Arctic Ocean since MIS 5: a comparison of sediment cores off the East Siberian and Chukchi margins

    Science.gov (United States)

    Xiao, W.; Wang, R.; Zhang, T.; Duan, X.; Polyak, L.

    2017-12-01

    In the Pleistocene the western Arctic Ocean was affected by deglacial discharge events from ice sheets in northern North America as well as the East Siberian and Chukchi margins. Distribution of Ice Rafted Debris (IRD) >250 μm and planktonic foraminiferal N. pachyderma (sin.) (Nps) δ18O and δ13C was compared in CHINARE sediment cores ARC2-M03 (Wang et al., 2013) and ARC3-P37 from the Chukchi Abyssal Plain and Northwind Ridge, respectively, to identify the impacts of icebergs and meltwater on paleoceanographic environments since MIS 5. The IRD is mainly composed of quartz grains and fragments of clastic rocks and detrital carbonates. The carbonates, mostly dolomites characteristic of the Canadian Arctic Archipelago (CAA) provenance, typically anti-correlate with quartz and clastic rocks, indicating different sources such as Chukchi-Alaskan or East Siberian margin. Most of the Nps δ18O depletions correspond to peaks in detrital carbonates, suggesting a strong influence of meltwater from the Laurentide Ice Sheet (LIS) on the western Arctic Ocean. A conspicuous dark gray interval interpreted to represent glacial/deglacial environments of MIS 4/3 age, shows a remarkable depletion in Nps δ13C along with high δ18O values and absence of IRD. This unusual signature may be related to a persistent sea-ice cover and/or high fluxes of terrigenous material with deglacial debris flows. In a younger grey interval corresponding to MIS2, high abundances of quartz and clastic rocks in the Northwind Ridge core ARC3-P37 indicate iceberg discharge from areas other than CAA, such as the Mackenzie LIS lobe or Chukchi-Alaskan margin. The MIS2-Holocene transition is marked by an increase in detrital carbonates co-occurring with Nps δ13C and δ18O depletion (Polyak et al., 2007), indicative of LIS iceberg/meltwater fluxes from the CAA. We note that stable-isotope events in the study area may go unnoticed because of gaps in foraminiferal records related to dissolution and/or adverse

  5. Impact of an Event Reporting System on Resident Complication Reporting in Plastic Surgery Training: Addressing an ACGME and Plastic Surgery Milestone Project Core Competency.

    Science.gov (United States)

    Parikh, Rajiv P; Snyder-Warwick, Alison; Naidoo, Sybill; Skolnick, Gary B; Patel, Kamlesh B

    2017-11-01

    The Accreditation Council for Graduate Medical Education and Plastic Surgery Milestone Project has identified practice-based learning and improvement, which involves systematically analyzing current practices and implementing changes, as a core competency in residency education. In surgical care, complication reporting is an essential component of practice-based learning and improvement as complications are analyzed in morbidity and mortality conference for quality improvement. Unfortunately, current methods for capturing a comprehensive profile of complications may significantly underestimate the true occurrence of complications. Therefore, the objectives of this study are to evaluate an intervention for complication reporting and compare this to current practice, in a plastic surgery training program. This is a preintervention and postintervention study evaluating resident reporting of complications on a plastic surgery service. The intervention was an online event reporting system developed by department leadership and patient safety experts. The cohorts consisted of all patients undergoing surgery during two separate 3-month blocks bridged by an implementation period. A trained reviewer recorded complications, and this served as the reference standard. Fisher's exact test was used for binary comparisons. There were 32 complications detected in 219 patients from June to August of 2015 and 35 complications in 202 patients from October to December of 2015. The proportion of complications reported in the preintervention group was nine of 32 (28.1 percent). After the intervention, this significantly increased to 32 of 35 (91.4 percent) (p < 0.001). An intervention using an event reporting system, supported by departmental leadership, led to significant improvements in complication reporting by plastic surgery residents.

  6. Analysis of emergency operating procedures effectiveness for core damage prevention using computer code RELAP for nuclear power plants with VVER-1000/B-320 in reference to primary to secondary circuit leak with external power loss and BRU-A stuck open failure

    International Nuclear Information System (INIS)

    Arkhangelski, L.; Sheveliov, D. V.

    1999-01-01

    This report presents analysis of development emergency operating procedures effectiveness for possible accident on nuclear power plant with WWER-1000 reactor type. Accident initiating event is the primary to secondary circuit leak caused by steam generator primary cover lift-up. In according to conservative assumptions the following additional failures were considered: dump valve BRU-A stuck open failure; loss of external power. The results of this work are represented as a comparative analysis of two possible ways of accident evolution: according to functioning automatic safety systems responses; according to accident management based on development emergency operating procedures with operator intervention. Developed emergency operating procedures assure the following significant goals to mitigate accident sequences: optimal use of ECCS water inventory; severe core damage prevention; mitigation of environment radioactive contamination. (authors)

  7. iROCS: Integrated accident management framework for coping with beyond-design-basis external events

    International Nuclear Information System (INIS)

    Kim, Jaewhan; Park, Soo-Yong; Ahn, Kwang-Il; Yang, Joon-Eon

    2016-01-01

    Highlights: • An integrated mitigating strategy to cope with extreme external events, iROCS, is proposed. • The strategy aims to preserve the integrity of the reactor vessel as well as core cooling. • A case study for an extreme damage state is performed to assess the effectiveness and feasibility of candidate mitigation strategies under an extreme event. - Abstract: The Fukushima Daiichi accident induced by the Great East Japan earthquake and tsunami on March 11, 2011, poses a new challenge to the nuclear society, especially from an accident management viewpoint. This paper presents a new accident management framework called an integrated, RObust Coping Strategy (iROCS) to cope with beyond-design-basis external events (BDBEEs). The iROCS approach is characterized by classification of various plant damage conditions (PDCs) that might be impacted by BDBEEs and corresponding integrated coping strategies for each of PDCs, aiming to maintain and restore core cooling (i.e., to prevent core damage) and to maintain the integrity of the reactor pressure vessel if it is judged that core damage may not be preventable in view of plant conditions. From a case study for an extreme damage condition, it showed that candidate accident management strategies should be evaluated from the viewpoint of effectiveness and feasibility against accident scenarios and extreme damage conditions of the site, especially when employing mobile or portable equipment under BDBEEs within the limited time available to achieve desired goals such as prevention of core damage as well as a reactor vessel failure.

  8. Radiation damage

    CERN Document Server

    Heijne, Erik H M; CERN. Geneva

    1998-01-01

    a) Radiation damage in organic materials. This series of lectures will give an overview of radiation effects on materials and components frequently used in accelerator engineering and experiments. Basic degradation phenomena will be presented for organic materials with comprehensive damage threshold doses for commonly used rubbers, thermoplastics, thermosets and composite materials. Some indications will be given for glass, scintillators and optical fibres. b) Radiation effects in semiconductor materials and devices. The major part of the time will be devoted to treat radiation effects in semiconductor sensors and the associated electronics, in particular displacement damage, interface and single event phenomena. Evaluation methods and practical aspects will be shown. Strategies will be developed for the survival of the materials under the expected environmental conditions of the LHC machine and detectors. I will describe profound revolution in our understanding of black holes and their relation to quantum me...

  9. Scale interactions in economics: application to the evaluation of the economic damages of climatic change and of extreme events; Interactions d'echelles en economie: application a l'evaluation des dommages economiques du changement climatique et des evenements extremes

    Energy Technology Data Exchange (ETDEWEB)

    Hallegatte, S

    2005-06-15

    Growth models, which neglect economic disequilibria, considered as temporary, are in general used to evaluate the damaging effects generated by climatic change. This work shows, through a series of modeling experiences, the importance of disequilibria and of endogenous variability of economy in the evaluation of damages due to extreme events and climatic change. It demonstrates the impossibility to separate the evaluation of damages from the representation of growth and of economic dynamics: the comfort losses will depend on both the nature and intensity of impacts and on the dynamics and situation of the economy to which they will apply. Thus, the uncertainties about the damaging effects of future climatic changes come from both scientific uncertainties and from uncertainties about the future organization of our economies. (J.S.)

  10. Analysis of core damage frequency: Nuclear power plant Dukovany, VVER/440 V-213 Unit 1, internal events. Volume 1: Main report

    International Nuclear Information System (INIS)

    Pugila, W.J.

    1994-01-01

    This report presents the final results from the Level 1 probabilistic safety assessment (PSA) for the Dukovany VVER/440 V-213 nuclear power plant, Unit 1. Section 1.1 describes the objectives of this study. Section 1.2 discusses the approach that was used for completing the Dukovany PSA. Section 1.3 summarizes the results of the PSA. Section 1.4 provides a comparison of the results of the Dukovany PSA with the results of other PSAs for different types of reactors worldwide. Section 1.5 summarizes the conclusions of the Dukovany PSA

  11. N reactor external events probabilistic risk assessment

    International Nuclear Information System (INIS)

    Baxter, J.T.

    1989-01-01

    An external events probabilistic risk assessment of the N Reactor has been completed. The methods used are those currently being proposed for external events analysis in NUREG-1150. Results are presented for the external hazards that survived preliminary screening. They are earthquake, fire, and external flood. Core damage frequencies for these hazards are shown to be comparable to those for commercial pressurized water reactors. Dominant fire sequences are described and related to 10 CFR 50, Appendix R design requirements. Potential remedial measures that reduce fire core damage risk are described including modifications to fire protection systems, procedure changes, and addition of new administrative controls. Dominant seismic sequences are described. The effect of non-safety support system dependencies on seismic risk is presented

  12. External event Probabilistic Risk Assessment for the High Flux Isotope Reactor (HFIR)

    International Nuclear Information System (INIS)

    Flanagan, G.F.; Johnson, D.H.; Buttemer, D.; Perla, H.F.; Chien, S.H.

    1989-01-01

    The High Flux Isotope Reactor (HFIR) is a high performance isotope production and research reactor which has been in operation at Oak Ridge National Laboratory (ORNL) since 1965. In late 1986 the reactor was shut down as a result of discovery of unexpected neutron embrittlement of the reactor vessel. In January of 1988 a level 1 Probabilistic Risk Assessment (PRA) (excluding external events) was published as part of the response to the many reviews that followed the shutdown and for use by ORNL to prioritize action items intended to upgrade the safety of the reactor. A conservative estimate of the core damage frequency initiated by internal events for HFIR was 3.11 x 10 -4 . In June 1989 a draft external events initiated PRA was published. The dominant contributions from external events came from seismic, wind, and fires. The overall external event contribution to core damage frequency is about 50% of the internal event initiated contribution and is dominated by seismic events

  13. [Public health, damage containment and the prevention of blood-borne and sexually transmitted infections: a review of the core concepts and their implementation in Brazil].

    Science.gov (United States)

    Elias, Lucília de Almeida; Bastos, Francisco Inacio

    2011-12-01

    This article assesses the historical context and the conceptual frame of setting up damage containment programs in the field of public health, with special emphasis on the Brazilian experience. The survey seeks to assess the relevance of such programs in the ongoing efforts to curb the spread of blood-borne and sexually transmitted infections, especially AIDS and hepatitis C. Findings from both the Brazilian and the international literature demonstrate that practical damage containment initiatives tend to be more effective when integrated with other public health measures based on common goals. Damage containment initiatives, aligned with the basic principles of public health do not limit themselves to a priori models or health care per se. They encompass a variety of pragmatic measures based on public policies and should be in line with the demands of the communities since the moment of their inception and implemented in the context of full partnership with such communities.

  14. Using NJOY99 and MCNP4B2 to Estimate the Radiation Damage Displacements per Atom per Second in Steel Within the Boiling Water Reactor Core Shroud and Vessel Wall from Reactor-Grade Mixed-Oxide/Uranium Oxide Fuel for the Nuclear Power Plant at Laguna Verde, Veracruz, Mexico

    International Nuclear Information System (INIS)

    Vickers, Lisa

    2003-01-01

    The government of Mexico has expressed interest in utilizing the Laguna Verde boiling water reactor (BWR) nuclear power plant for the disposition of reprocessed spent uranium oxide (UOX) fuel in the form of reactor-grade mixed-oxide (MOX) fuel. MOX fuel would replace spent UOX fuel as a fraction in the core from 18 to 30% depending on the fuel loading cycle. MOX fuel is expected to increase the neutron fluence, flux, fuel centerline temperature, reactor core pressure, and yield higher energy neutrons.There is concern that a core with a fraction of MOX fuel (i.e., increased 239 Pu wt%) would increase the radiation damage displacements per atom per second (dpa-s -1 ) in steel within the core shroud and vessel wall as compared to only conventional, enriched UOX fuel in the core. The evaluation of radiation damage within the core shroud and vessel wall is a concern because of the potentially adverse affect to personnel and public safety, environment, and operating life of the reactor.The primary uniqueness of this paper is the computation of radiation damage (dpa-s -1 ) using NJOY99-processed cross sections for steel within the core shroud and vessel wall. Specifically, the unique radiation damage results are several orders of magnitude greater than results of previous works. In addition, the conclusion of this paper was that the addition of the maximum fraction of one-third MOX fuel to the LV1 BWR core did significantly increase the radiation damage in steel within the core shroud and vessel wall such that without mitigation of radiation damage by periodic thermal annealing or reduction in operating parameters such as neutron fluence, core temperature, and pressure, it posed a potentially adverse affect to the personnel and public safety, environment, and operating life of the reactor

  15. Metabolite Damage and Metabolite Damage Control in Plants

    Energy Technology Data Exchange (ETDEWEB)

    Hanson, Andrew D. [Horticultural Sciences Department and; Henry, Christopher S. [Mathematics and Computer Science Division, Argonne National Laboratory, Argonne, Illinois 60439, email:; Computation Institute, University of Chicago, Chicago, Illinois 60637; Fiehn, Oliver [Genome Center, University of California, Davis, California 95616, email:; de Crécy-Lagard, Valérie [Microbiology and Cell Science Department, University of Florida, Gainesville, Florida 32611, email: ,

    2016-04-29

    It is increasingly clear that (a) many metabolites undergo spontaneous or enzyme-catalyzed side reactions in vivo, (b) the damaged metabolites formed by these reactions can be harmful, and (c) organisms have biochemical systems that limit the buildup of damaged metabolites. These damage-control systems either return a damaged molecule to its pristine state (metabolite repair) or convert harmful molecules to harmless ones (damage preemption). Because all organisms share a core set of metabolites that suffer the same chemical and enzymatic damage reactions, certain damage-control systems are widely conserved across the kingdoms of life. Relatively few damage reactions and damage-control systems are well known. Uncovering new damage reactions and identifying the corresponding damaged metabolites, damage-control genes, and enzymes demands a coordinated mix of chemistry, metabolomics, cheminformatics, biochemistry, and comparative genomics. This review illustrates the above points using examples from plants, which are at least as prone to metabolite damage as other organisms.

  16. New concept of damage evaluation method for core internal materials considering radiation induced stress relaxation (1). Experiments and modeling of radiation effects

    International Nuclear Information System (INIS)

    Miwa, Yukio; Kondo, Keietsu; Okubo, Nariaki; Kaji, Yoshiyuki; Tsukada, Takashi

    2009-01-01

    In order to build the new concept of material damage evaluation method, synergistic effect of radiation and residual stress on material degradation was estimated experimentally, and the effect of radiation induced stress relaxation on retardation of material degradation was observed. (author)

  17. Evaluation of external hazards to nuclear power plants in the United States: Other external events

    International Nuclear Information System (INIS)

    Kimura, C.Y.; Prassinos, P.G.

    1989-02-01

    In support of implementation of the Nuclear Regulatory Commission's Severe Accident Policy, the Lawrence Livermore National Laboratory (LLNL) has performed a study of the risk of core damage to nuclear power plants in the United States due to ''other external events.'' The broad objective has been to gain an understanding of whether ''other external events'' (the hazards not covered by previous reports) are among the major potential accident initiators that may pose a threat of severe reactor core damage or of large radioactive release to the environment from the reactor. The ''other external events'' covered in this report are nearby industrial/military facility accidents, on site hazardous material storage accidents, severe temperature transients, severe weather storms, lightning strikes, external fires, extraterrestrial activity, volcanic activity, earth movement, and abrasive windstorms. The analysis was based on two figures-of-merit, one based on core damage frequency and the other based on the frequency of large radioactive releases. 37 refs., 8 tabs

  18. Evaluation of potential severe accidents during low power and shutdown operations at Surry, Unit 1: Analysis of core damage frequency from internal fires during mid-loop operations. Volume 3, Part 1, Main report

    International Nuclear Information System (INIS)

    Musicki, Z.; Chu, T.L.; Yang, J.; Ho, V.; Hou, Y.M.; Lin, J.; Siu, N.

    1994-07-01

    During l989, the Nuclear Regulatory Commission (NRC) initiated an extensive program to carefully examine the potential risks during low power and shutdown operations. The program includes two parallel projects being performed by Brookhaven National Laboratory (BNL) and Sandia National Laboratories (SNL). Two plants, Surry (pressurized water reactor) and Grand Gulf (boiling water reactor), were selected as the plants to be studied. The objectives of the program are to assess the risks of severe accidents initiated during plant operational states other than fun power operation and to compare the estimated core damage frequencies, important accident sequences and other qualitative and quantitative results with those accidents initiated during full power operation as assessed in NUREG-1150. The objective of this report is to document the approach utilized in ' the Surry plant and discuss the results obtained. A parallel report for the Grand Gulf plant is prepared by SNL. This study shows that the core-damage frequency during mid-loop operation at the Surry plant is comparable to that of power operation. We recognize that there is very large uncertainty in the human error probabilities in this study. This study identified that only a few. procedures are available for mitigating accidents that may occur during shutdown. Procedures written specifically for shutdown accidents would be useful

  19. A review for identification of initiating events in event tree development process on nuclear power plants

    International Nuclear Information System (INIS)

    Riyadi, Eko H.

    2014-01-01

    Initiating event is defined as any event either internal or external to the nuclear power plants (NPPs) that perturbs the steady state operation of the plant, if operating, thereby initiating an abnormal event such as transient or loss of coolant accident (LOCA) within the NPPs. These initiating events trigger sequences of events that challenge plant control and safety systems whose failure could potentially lead to core damage or large early release. Selection for initiating events consists of two steps i.e. first step, definition of possible events, such as by evaluating a comprehensive engineering, and by constructing a top level logic model. Then the second step, grouping of identified initiating event's by the safety function to be performed or combinations of systems responses. Therefore, the purpose of this paper is to discuss initiating events identification in event tree development process and to reviews other probabilistic safety assessments (PSA). The identification of initiating events also involves the past operating experience, review of other PSA, failure mode and effect analysis (FMEA), feedback from system modeling, and master logic diagram (special type of fault tree). By using the method of study for the condition of the traditional US PSA categorization in detail, could be obtained the important initiating events that are categorized into LOCA, transients and external events

  20. A review for identification of initiating events in event tree development process on nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Riyadi, Eko H., E-mail: e.riyadi@bapeten.go.id [Center for Regulatory Assessment of Nuclear Installation and Materials, Nuclear Energy Regulatory Agency (BAPETEN), Jl. Gajah Mada 8 Jakarta 10120 (Indonesia)

    2014-09-30

    Initiating event is defined as any event either internal or external to the nuclear power plants (NPPs) that perturbs the steady state operation of the plant, if operating, thereby initiating an abnormal event such as transient or loss of coolant accident (LOCA) within the NPPs. These initiating events trigger sequences of events that challenge plant control and safety systems whose failure could potentially lead to core damage or large early release. Selection for initiating events consists of two steps i.e. first step, definition of possible events, such as by evaluating a comprehensive engineering, and by constructing a top level logic model. Then the second step, grouping of identified initiating event's by the safety function to be performed or combinations of systems responses. Therefore, the purpose of this paper is to discuss initiating events identification in event tree development process and to reviews other probabilistic safety assessments (PSA). The identification of initiating events also involves the past operating experience, review of other PSA, failure mode and effect analysis (FMEA), feedback from system modeling, and master logic diagram (special type of fault tree). By using the method of study for the condition of the traditional US PSA categorization in detail, could be obtained the important initiating events that are categorized into LOCA, transients and external events.

  1. Sensitivity studies on the approaches for addressing multiple initiating events in fire events PSA

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Il; Lim, Ho Gon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    A single fire event within a fire compartment or a fire scenario can cause multiple initiating events (IEs). As an example, a fire in a turbine building fire area can cause a loss of the main feed-water (LOMF) and loss of off-site power (LOOP) IEs. Previous domestic fire events PSA had considered only the most severe initiating event among multiple initiating events. NUREG/CR-6850 and ANS/ASME PRA Standard require that multiple IEs are to be addressed in fire events PSA. In this paper, sensitivity studies on the approaches for addressing multiple IEs in fire events PSA for Hanul Unit 3 were performed and their results were presented. In this paper, sensitivity studies on the approaches for addressing multiple IEs in fire events PSA are performed and their results were presented. From the sensitivity analysis results, we can find that the incorporations of multiple IEs into fire events PSA model result in the core damage frequency (CDF) increase and may lead to the generation of the duplicate cutsets. Multiple IEs also can occur at internal flooding event or other external events such as seismic event. They should be considered in the constructions of PSA models in order to realistically estimate risk due to flooding or seismic events.

  2. Best estimate plus uncertainty analysis of departure from nucleate boiling limiting case with CASL core simulator VERA-CS in response to PWR main steam line break event

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C.S., E-mail: csbrown3@ncsu.edu [Department of Nuclear Engineering, North Carolina State University, 2500 Stinson Drive, Raleigh, NC 27695-7909 (United States); Zhang, H., E-mail: Hongbin.Zhang@inl.gov [Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID 83415-3870 (United States); Kucukboyaci, V., E-mail: kucukbvn@westinghouse.com [Westinghouse Electric Company, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States); Sung, Y., E-mail: sungy@westinghouse.com [Westinghouse Electric Company, 1000 Westinghouse Drive, Cranberry Township, PA 16066 (United States)

    2016-12-01

    Highlights: • Best estimate plus uncertainty (BEPU) analyses of PWR core responses under main steam line break (MSLB) accident. • CASL’s coupled neutron transport/subchannel code VERA-CS. • Wilks’ nonparametric statistical method. • MDNBR 95/95 tolerance limit. - Abstract: VERA-CS (Virtual Environment for Reactor Applications, Core Simulator) is a coupled neutron transport and thermal-hydraulics subchannel code under development by the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS was applied to simulate core behavior of a typical Westinghouse-designed 4-loop pressurized water reactor (PWR) with 17 × 17 fuel assemblies in response to two main steam line break (MSLB) accident scenarios initiated at hot zero power (HZP) at the end of the first fuel cycle with the most reactive rod cluster control assembly stuck out of the core. The reactor core boundary conditions at the most DNB limiting time step were determined by a system analysis code. The core inlet flow and temperature distributions were obtained from computational fluid dynamics (CFD) simulations. The two MSLB scenarios consisted of the high and low flow situations, where reactor coolant pumps either continue to operate with offsite power or do not continue to operate since offsite power is unavailable. The best estimate plus uncertainty (BEPU) analysis method was applied using Wilks’ nonparametric statistical approach. In this demonstration of BEPU application, 59 full core simulations were performed for each accident scenario to provide the minimum departure from nucleate boiling ratio (MDNBR) at the 95/95 (95% probability with 95% confidence level) tolerance limit. A parametric goodness-of-fit approach was also applied to the results to obtain the MDNBR value at the 95/95 tolerance limit. Initial sensitivity analysis was performed with the 59 cases per accident scenario by use of Pearson correlation coefficients. The results show that this typical PWR core

  3. Best estimate plus uncertainty analysis of departure from nucleate boiling limiting case with CASL core simulator VERA-CS in response to PWR main steam line break event

    International Nuclear Information System (INIS)

    Brown, C.S.; Zhang, H.; Kucukboyaci, V.; Sung, Y.

    2016-01-01

    Highlights: • Best estimate plus uncertainty (BEPU) analyses of PWR core responses under main steam line break (MSLB) accident. • CASL’s coupled neutron transport/subchannel code VERA-CS. • Wilks’ nonparametric statistical method. • MDNBR 95/95 tolerance limit. - Abstract: VERA-CS (Virtual Environment for Reactor Applications, Core Simulator) is a coupled neutron transport and thermal-hydraulics subchannel code under development by the Consortium for Advanced Simulation of Light Water Reactors (CASL). VERA-CS was applied to simulate core behavior of a typical Westinghouse-designed 4-loop pressurized water reactor (PWR) with 17 × 17 fuel assemblies in response to two main steam line break (MSLB) accident scenarios initiated at hot zero power (HZP) at the end of the first fuel cycle with the most reactive rod cluster control assembly stuck out of the core. The reactor core boundary conditions at the most DNB limiting time step were determined by a system analysis code. The core inlet flow and temperature distributions were obtained from computational fluid dynamics (CFD) simulations. The two MSLB scenarios consisted of the high and low flow situations, where reactor coolant pumps either continue to operate with offsite power or do not continue to operate since offsite power is unavailable. The best estimate plus uncertainty (BEPU) analysis method was applied using Wilks’ nonparametric statistical approach. In this demonstration of BEPU application, 59 full core simulations were performed for each accident scenario to provide the minimum departure from nucleate boiling ratio (MDNBR) at the 95/95 (95% probability with 95% confidence level) tolerance limit. A parametric goodness-of-fit approach was also applied to the results to obtain the MDNBR value at the 95/95 tolerance limit. Initial sensitivity analysis was performed with the 59 cases per accident scenario by use of Pearson correlation coefficients. The results show that this typical PWR core

  4. CTCAE v.3.0 in evaluation the radiation adverse events in cancer patients after pelvic irradiation (Contemporary mechanisms of radiation and comprehensive damage after cancer treatment)

    International Nuclear Information System (INIS)

    Encheva, E.; Zahariev, Z.; Sultanov, B.; Hadjieva, T.

    2010-01-01

    The authors present the first report of applying the NCI CTCAE v.3.0 for evaluation of radiation adverse events in Bulgaria. The adverse events are observed in early stage cervical and endometrial cancer patients receiving external beam radiotherapy after radical surgery during the radiotherapy and 3 months after it ended. The paper discusses the contemporary concepts of the normal tissue morbidity, the issue early-late adverse events, comprehensive factors and causes, except irradiation, involved in their occurrence. The possibility to define the single method contribution of the comprehensive cancer treatment for development of post-treatment adverse events in cancer survivors in effort to improve their quality of life is discussed. (authors)

  5. SENTINEL EVENTS

    Directory of Open Access Journals (Sweden)

    Andrej Robida

    2004-09-01

    Full Text Available Background. The Objective of the article is a two year statistics on sentinel events in hospitals. Results of a survey on sentinel events and the attitude of hospital leaders and staff are also included. Some recommendations regarding patient safety and the handling of sentinel events are given.Methods. In March 2002 the Ministry of Health introduce a voluntary reporting system on sentinel events in Slovenian hospitals. Sentinel events were analyzed according to the place the event, its content, and root causes. To show results of the first year, a conference for hospital directors and medical directors was organized. A survey was conducted among the participants with the purpose of gathering information about their view on sentinel events. One hundred questionnaires were distributed.Results. Sentinel events. There were 14 reports of sentinel events in the first year and 7 in the second. In 4 cases reports were received only after written reminders were sent to the responsible persons, in one case no reports were obtained. There were 14 deaths, 5 of these were in-hospital suicides, 6 were due to an adverse event, 3 were unexplained. Events not leading to death were a suicide attempt, a wrong side surgery, a paraplegia after spinal anaesthesia, a fall with a femoral neck fracture, a damage of the spleen in the event of pleural space drainage, inadvertent embolization with absolute alcohol into a femoral artery and a physical attack on a physician by a patient. Analysis of root causes of sentinel events showed that in most cases processes were inadequate.Survey. One quarter of those surveyed did not know about the sentinel events reporting system. 16% were having actual problems when reporting events and 47% beleived that there was an attempt to blame individuals. Obstacles in reporting events openly were fear of consequences, moral shame, fear of public disclosure of names of participants in the event and exposure in mass media. The majority of

  6. External Events PSA for the Paks NPP

    International Nuclear Information System (INIS)

    Bareith, Attila; Karsa, Zoltan; Siklossy, Tamas; Vida, Zoltan

    2014-01-01

    Initially, probabilistic safety assessment of external events was limited to the analysis of earthquakes for the Paks Nuclear Power Plant in Hungary. The level 1 seismic PSA was completed in 2002 showing a significant contribution of seismic failures to core damage risk. Although other external events of natural origin had previously been screened out from detailed plant PSA mostly on the basis of event frequencies, a review of recent experience on extreme weather phenomena made during the periodic safety review of the plant led to the initiation of PSA for external events other than earthquakes in 2009. In the meantime, the accident of the Fukushima Dai-ichi Nuclear Power Plant confirmed further the importance of such an analysis. The external event PSA for the Paks plant followed the commonly known steps: selection and screening of external hazards, hazard assessment for screened-in external events, analysis of plant response and fragility, PSA model development, and risk quantification and interpretation of results. As a result of event selection and screening the following weather related external hazards were subject to detailed analysis: extreme wind, extreme rainfall (precipitation), extreme snow, extremely high and extremely low temperatures, lightning, frost and ice formation. The analysis proved to be a significant challenge due to scarcity of data, lack of knowledge, as well as limitations of existing PSA methodologies. This paper presents an overview of the external events PSA performed for the Paks NPP. Important methodological aspects are summarised. Key analysis findings and unresolved issues that need further elaboration are highlighted. Development of external events PSA for the Paks NPP was completed by the end of 2012. The analysis followed the commonly known steps: selection and screening of external hazards, hazard assessment for screened-in external events, analysis of plant response and fragility, PSA model development, and risk

  7. Evidence of Himalayan erosional event at approx. 0.5 Ma from a sediment core from the equatorial Indian Ocean in the vicinityof ODP Leg 116 sites

    Digital Repository Service at National Institute of Oceanography (India)

    Nath, B.N.; Gupta, S.M.; Mislankar, P.G.; Rao, B.R.; Parthiban, G.; Roelandts, I.; Patil, S.K.

    ; discrimination plots of Ca/Ti versus K/Ti and K sub(2)O/Al sub(2) O sub(3) and La/Yb ratios suggest a highly metamorphosed source such as higher Himalayan crystalline (HHC) series indicating two events of increased physical weathering and erosion in the Himalayan...

  8. Review and analysis for events of damage of electric circuits for safe shutdown in postulated fires at PWR power plants and countermeasures for preventing loss of inventory water caused by malfunction of valves

    Energy Technology Data Exchange (ETDEWEB)

    Shimada, Hiroki [Inst. of Nuclear Safety System Inc., Mihama, Fukui (Japan)

    2002-09-01

    The United States Nuclear Regulatory Commission (NRC) has been collecting reports on events concerning postulated fires from the viewpoint of fire protection for nuclear power plants. First of all, we reviewed these reports on the US nuclear power plants and analyzed (1) location of a fire, (2) part where the fire occurred and (3) the cause of the fire. The results revealed that the postulated fires had often occurred in areas dense with cables, such as central control rooms and cable connecting rooms, and the events caused by ground faults and short circuits resulting from cable fires had been predominant. Then, a comparison was made between PWRs in the United States and those in Japan in terms of the items and details of analysis on fire-caused damage of the electric circuits as described above. The comparison revealed that ''the event of loss of inventory water resulting from malfunction of valves caused by a fire'' was given consideration at the PWRs in the United States but not for those in Japan. Accordingly, countermeasures against this event were proposed. (author)

  9. Proteomics Core

    Data.gov (United States)

    Federal Laboratory Consortium — Proteomics Core is the central resource for mass spectrometry based proteomics within the NHLBI. The Core staff help collaborators design proteomics experiments in a...

  10. Proceeding of 31st domestic symposium on failure events and integrity evaluation of nuclear power generation facilities

    International Nuclear Information System (INIS)

    2003-07-01

    As the 31st domestic symposium of Atomic Energy Research Committee, the Japan Welding Engineering Society, the symposium was held titled as 'Damage events and integrity evaluations of nuclear power facilities'. Six speakers gave lectures titled as 'Damages of structural materials in the LWR plants and their measures', 'Inspection and integrity evaluation method of SCC in the BWR plants', 'Measures with chloride SCC of piping', 'High cycle fatigue damage events of small diameter pipes and their measures', 'Management of SCC in in-core instrumentation thimbles' and 'Japanese lost ten years and American and other leaps'. (T. Tanaka)

  11. Long-term follow-up after near-infrared spectroscopy coronary imaging: Insights from the lipid cORe plaque association with CLinical events (ORACLE-NIRS) registry.

    Science.gov (United States)

    Danek, Barbara Anna; Karatasakis, Aris; Karacsonyi, Judit; Alame, Aya; Resendes, Erica; Kalsaria, Pratik; Nguyen-Trong, Phuong-Khanh J; Rangan, Bavana V; Roesle, Michele; Abdullah, Shuaib; Banerjee, Subhash; Brilakis, Emmanouil S

    Coronary lipid core plaque may be associated with the incidence of subsequent cardiovascular events. We analyzed outcomes of 239 patients who underwent near-infrared spectroscopy (NIRS) coronary imaging between 2009-2011. Multivariable Cox regression was used to identify variables independently associated with the incidence of major adverse cardiovascular events (MACE; cardiac mortality, acute coronary syndromes (ACS), stroke, and unplanned revascularization) during follow-up. Mean patient age was 64±9years, 99% were men, and 50% were diabetic, presenting with stable coronary artery disease (61%) or an acute coronary syndrome (ACS, 39%). Target vessel pre-stenting median lipid core burden index (LCBI) was 88 [interquartile range, IQR 50-130]. Median LCBI in non-target vessels was 57 [IQR 26-94]. Median follow-up was 5.3years. The 5-year MACE rate was 37.5% (cardiac mortality was 15.0%). On multivariable analysis the following variables were associated with MACE: diabetes mellitus, prior percutaneous coronary intervention performed at index angiography, and non-target vessel LCBI. Non-target vessel LCBI of 77 was determined using receiver-operating characteristic curve analysis to be a threshold for prediction of MACE in our cohort. The adjusted hazard ratio (HR) for non-target vessel LCBI ≥77 was 14.05 (95% confidence interval (CI) 2.47-133.51, p=0.002). The 5-year cumulative incidence of events in the above-threshold group was 58.0% vs. 13.1% in the below-threshold group. During long-term follow-up of patients who underwent NIRS imaging, high LCBI in a non-PCI target vessel was associated with increased incidence of MACE. Published by Elsevier Inc.

  12. Saphenous vein graft near-infrared spectroscopy imaging insights from the lipid core plaque association with clinical events near-infrared spectroscopy (ORACLE-NIRS) registry.

    Science.gov (United States)

    Danek, Barbara A; Karatasakis, Aris; Alame, Aya J; Nguyen-Trong, Phuong-Khanh J; Karacsonyi, Judit; Rangan, Bavana; Roesle, Michele; Atwell, Amy; Resendes, Erica; Martinez-Parachini, Jose Roberto; Iwnetu, Rahel; Kalsaria, Pratik; Siddiqui, Furqan; Muller, James E; Banerjee, Subhash; Brilakis, Emmanouil

    2017-05-01

    We sought to examine near-infrared spectroscopy (NIRS) imaging findings of aortocoronary saphenous vein grafts (SVGs). SVGs are prone to develop atherosclerosis similar to native coronary arteries. They have received little study using NIRS. We examined the clinical characteristics and imaging findings from 43 patients who underwent NIRS imaging of 45 SVGs at our institution between 2009 and 2016. The mean patient age was 67 ± 7 years and 98% were men, with high prevalence of diabetes mellitus (56%), hypertension (95%), and dyslipidemia (95%). Mean SVG age was 7 ± 7 years, mean SVG lipid core burden index (LCBI) was 53 ± 60 and mean maxLCBI 4 mm was 194 ± 234. Twelve SVGs (27%) had lipid core plaques (2 yellow blocks on the block chemogram), with a higher prevalence in SVGs older than 5 years (46% vs. 5%, P = 0.002). Older SVG age was associated with higher LCBI (r = 0.480, P < 0.001) and higher maxLCBI 4 mm (r = 0.567, P < 0.001). On univariate analysis, greater annual total cholesterol exposure was associated with higher SVG LCBI (r = 0.30, P = 0.042) and annual LDL-cholesterol and triglyceride exposure were associated with higher SVG maxLCBI 4 mm (LDL-C: r = 0.41, P = 0.020; triglycerides: r = 0.36, P = 0.043). On multivariate analysis, the only independent predictor of SVG LCBI and maxLCBI 4mm was SVG age. SVG percutaneous coronary intervention was performed in 63% of the patients. An embolic protection device was used in 96% of SVG PCIs. Periprocedural myocardial infarction occurred in one patient. Older SVG age and greater lipid exposure are associated with higher SVG lipid burden. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  13. Can tokamaks PFC survive a single event of any plasma instabilities?

    Energy Technology Data Exchange (ETDEWEB)

    Hassanein, A., E-mail: hassanein@purdue.edu [Center for Materials under Extreme Environment, School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States); Sizyuk, V.; Miloshevsky, G.; Sizyuk, T. [Center for Materials under Extreme Environment, School of Nuclear Engineering, Purdue University, 400 Central Drive, West Lafayette, IN 47907 (United States)

    2013-07-15

    Plasma instability events such as disruptions, edge-localized modes (ELMs), runaway electrons (REs), and vertical displacement events (VDEs) are continued to be serious events and most limiting factors for successful tokamak reactor concept. The plasma-facing components (PFCs), e.g., wall, divertor, and limited surfaces of a tokamak as well as coolant structure materials are subjected to intense particle and heat loads and must maintain a clean and stable surface environment among them and the core/edge plasma. Typical ITER transient events parameters are used for assessing the damage from these four different instability events. HEIGHTS simulation showed that a single event of a disruption, giant ELM, VDE, or RE can cause significant surface erosion (melting and vaporization) damage to PFC, nearby components, and/or structural materials (VDE, RE) melting and possible burnout of coolant tubes that could result in shut down of reactor for extended repair time.

  14. Can tokamaks PFC survive a single event of any plasma instabilities?

    Science.gov (United States)

    Hassanein, A.; Sizyuk, V.; Miloshevsky, G.; Sizyuk, T.

    2013-07-01

    Plasma instability events such as disruptions, edge-localized modes (ELMs), runaway electrons (REs), and vertical displacement events (VDEs) are continued to be serious events and most limiting factors for successful tokamak reactor concept. The plasma-facing components (PFCs), e.g., wall, divertor, and limited surfaces of a tokamak as well as coolant structure materials are subjected to intense particle and heat loads and must maintain a clean and stable surface environment among them and the core/edge plasma. Typical ITER transient events parameters are used for assessing the damage from these four different instability events. HEIGHTS simulation showed that a single event of a disruption, giant ELM, VDE, or RE can cause significant surface erosion (melting and vaporization) damage to PFC, nearby components, and/or structural materials (VDE, RE) melting and possible burnout of coolant tubes that could result in shut down of reactor for extended repair time.

  15. Can tokamaks PFC survive a single event of any plasma instabilities?

    International Nuclear Information System (INIS)

    Hassanein, A.; Sizyuk, V.; Miloshevsky, G.; Sizyuk, T.

    2013-01-01

    Plasma instability events such as disruptions, edge-localized modes (ELMs), runaway electrons (REs), and vertical displacement events (VDEs) are continued to be serious events and most limiting factors for successful tokamak reactor concept. The plasma-facing components (PFCs), e.g., wall, divertor, and limited surfaces of a tokamak as well as coolant structure materials are subjected to intense particle and heat loads and must maintain a clean and stable surface environment among them and the core/edge plasma. Typical ITER transient events parameters are used for assessing the damage from these four different instability events. HEIGHTS simulation showed that a single event of a disruption, giant ELM, VDE, or RE can cause significant surface erosion (melting and vaporization) damage to PFC, nearby components, and/or structural materials (VDE, RE) melting and possible burnout of coolant tubes that could result in shut down of reactor for extended repair time

  16. The forecast of mining-induced seismicity and the consequent risk of damage to the excavation in the area of seismic event

    Directory of Open Access Journals (Sweden)

    Jan Drzewiecki

    2017-01-01

    Full Text Available The Central Mining Institute has developed a method for forecasting the amount of seismic energy created by tremors induced by mining operations. The results of geophysical measurements of S wave velocity anomalies in a rock mass or the results of analytic calculations of the values of pressure on the horizon of the elastic layers are used in the process of calculating the energy. The calculation program which has been developed and adopted has been modified over recent years and it now enables not only the prediction of the energy of dynamic phenomena induced by mining but also the forecasting of the devastating range of seismic shock. The results obtained from this calculation, usually presented in a more readable graphic form, are useful for the macroscopic evaluation of locations that are potential sources of seismic energy. Forecasting of the maximum energy of seismic shock without prior knowledge of the location of the shock's source, does not allow shock attenuation that results from, for example, a distance of tremor source from the excavation which will be affected by seismic energy, to be taken into consideration. The phenomena of energy dissipation, which is taken into account in the forecasts, create a new quality of assessment of threat to the excavation. The paper presents the principle of a method of forecasting the seismic energy of a shock and the risk of damage to the excavation as a result of the impact of its energy wave. The solution assumes that the source of the energy shock is a resilient layer in which the sum of the gravitational stresses, resulting from natural disturbances and those induced by the conducted or planned mining exploitation, is estimated. The proposed solution assumes a spherical model for the tremor source, for which seismic energy is forecasted as a function of the longwall advance and the elementary value of seismic energy destroying the excavation. Subsequently, the following are calculated for the

  17. Core evidence of paleoseismic events in Paleogene deposits of the Shulu Sag in the Bohai Bay Basin, east China, and their petroleum geologic significance

    Science.gov (United States)

    Zheng, Lijing; Jiang, Zaixing; Liu, Hui; Kong, Xiangxin; Li, Haipeng; Jiang, Xiaolong

    2015-10-01

    The Shulu Sag, located in the southwestern corner of the Jizhong Depression, Bohai Bay Basin of east China, is a NE-SW trending, elongate Cenozoic half-graben basin. The lowermost part of the third member of the Shahejie Formation in this basin is characterized by continental rudstone and calcilutite to calcisiltite facies. Based on core observation and regional geologic analysis, seismites are recognized in these lacustrine deposits, which include soft-sediment deformation structures (sedimentary dikes, hydraulic shattering, diapir structures, convolute lamination, load-flame structures, ball-and-pillow structures, loop bedding, and subsidence structures), synsedimentary faults, and seismoturbidites. In addition, mixed-source rudstones, consisting of the Paleozoic carbonate clasts and in situ calcilutite clasts in the lowermost submember of Shahejie 3, appear in the seismites, suggesting an earthquake origin. A complete representative vertical sequence in the lowermost part of the third member found in well ST1H located in the central part of the Shulu Sag shows, from the base to the top: underlying undeformed layers, synsedimentary faults, liquefied carbonate rocks, allogenetic seismoturbidites, and overlying undeformed layers. Seismites are widely distributed around this well and there are multiple sets of stacked seismites separated by undeformed sediment. The nearby NW-trending Taijiazhuang fault whose fault growth index is from 1.1 to 1.8 and the NNE-trending Xinhe fault with a fault growth index of 1.3-1.9 may be the source of the instability to create the seismites. These deformed sedimentary layers are favorable for the accumulation of oil and gas; for example, sedimentary dikes can cut through many layers and serve as conduits for fluid migration. Sedimentary faults and fractures induced by earthquakes can act as oil and gas migration channels or store petroleum products as well. Seismoturbidites and mixed-source rudstones are excellent reservoirs due to

  18. Analysis of extreme events

    CSIR Research Space (South Africa)

    Khuluse, S

    2009-04-01

    Full Text Available ) determination of the distribution of the damage and (iii) preparation of products that enable prediction of future risk events. The methodology provided by extreme value theory can also be a powerful tool in risk analysis...

  19. TMI-2 core examination plan

    International Nuclear Information System (INIS)

    Owen, D.E.; MacDonald, P.E.; Hobbins, R.R.; Ploggr, S.A.

    1982-01-01

    The Three Mile Island (TMI-2) core examination is divided into four stages: (1) before removing the head; (2) before removing the plenum; (3) during defueling; and (4) offsite examinations. Core examinations recommended during the first three stages are primarily devoted to documenting the post-accident condition of the core. The detailed analysis of core damage structures will be performed during offsite examinations at government and commercial hot cell facilities. The primary objectives of these examinations are to enhance the understanding of the degraded core accident sequence, to develop the technical bases for reactor regulations, and to improve LWR design and operation

  20. Enrichment Of Volcanogenic Trace Elements, Co, Cr, Cu, Ni, Mo And Zr In A Continuous Subsurface Eagle Ford Core In South Texas And Origin Of The Oceanic Anoxic Event II At The Cenomanian-Turonian (C/T) Boundary

    Science.gov (United States)

    Valencia, D.; Basu, A. R.; Loocke, M. P.

    2017-12-01

    The Eagle Ford Formation containing the Cenomanian-Turonian (C/T) boundary continues to be studied globally not only for its economic potential and analog for `frack-able' unconventional organic-rich formations, but it is of particular interest to researchers because it was deposited across the C/T boundary recording an Oceanic Anoxic Event (OAE2). OAEs are short lived episodes (matter into the sedimentary record remains enigmatic. Geochemical and geochronological analysis of a subsurface 300ft long continuous core of the Eagle Ford Formation of South Texas shows evidence for volcanism throughout. This is confirmed by multiple thin intermittent bentonite beds. The whole rock black shale (marl) shows elevated concentrations of volcanogenic trace elements (Co, Cr, Cu, Ni, Mo and Zn) throughout the core. By sampling bentonite bed zircons near the inferred C/T boundary, U-Pb age of 93.2 ±1.7 Ma for the Eagle Ford is established. Using this horizon, the onset of OAE2 is constrained and well-correlated with the positive δ13C excursion. For the trace element analysis, the core was sampled at 10ft intervals for ICP-MS. The analytical results show significantly increased volcanogenic trace metal input correlating with increased Total Organic Carbon and positive δ13C values at the C/T dated zircon horizon. OAE2, defined by the positive δ13C excursion, was found to span over an interval of 85ft. With a definitive constraint for OAE2 established, this well-defined interval was analyzed at a much higher resolution using ED-XRF. The core was then sampled at 6' intervals throughout the C/T boundary at OAE2. The high-resolution sampling of the core shows 80-99% increase in abundance of Co, Cr, Cu, Ni, Mo, Zn over the average Post Australian Archean Shale(PAAS), representative of average continental crust. These volcanogenic-rich intervals reach peak values before the onset of OAE2 and at the maximum values for the positive δ13C isotope excursion directly after the 93.2 ±1

  1. External event analysis methods for NUREG-1150

    International Nuclear Information System (INIS)

    Bohn, M.P.; Lambright, J.A.

    1989-01-01

    The US Nuclear Regulatory Commission is sponsoring probabilistic risk assessments of six operating commercial nuclear power plants as part of a major update of the understanding of risk as provided by the original WASH-1400 risk assessments. In contrast to the WASH-1400 studies, at least two of the NUREG-1150 risk assessments will include an analysis of risks due to earthquakes, fires, floods, etc., which are collectively known as eternal events. This paper summarizes the methods to be used in the external event analysis for NUREG-1150 and the results obtained to date. The two plants for which external events are being considered are Surry and Peach Bottom, a PWR and BWR respectively. The external event analyses (through core damage frequency calculations) were completed in June 1989, with final documentation available in September. In contrast to most past external event analyses, wherein rudimentary systems models were developed reflecting each external event under consideration, the simplified NUREG-1150 analyses are based on the availability of the full internal event PRA systems models (event trees and fault trees) and make use of extensive computer-aided screening to reduce them to sequence cut sets important to each external event. This provides two major advantages in that consistency and scrutability with respect to the internal event analysis is achieved, and the full gamut of random and test/maintenance unavailabilities are automatically included, while only those probabilistically important survive the screening process. Thus, full benefit of the internal event analysis is obtained by performing the internal and external event analyses sequentially

  2. Performance of collision damage mitigation braking systems and their effects on human injury in the event of car-to-pedestrian accidents.

    Science.gov (United States)

    Matsui, Yasuhiro; Han, Yong; Mizuno, Koji

    2011-11-01

    The number of traffic deaths in Japan was 4,863 in 2010. Pedestrians account for the highest number (1,714, 35%), and vehicle occupants the second highest (1,602, 33%). Pedestrian protection is a key countermeasure to reduce casualties in traffic accidents. A striking vehicle's impact velocity could be considered a parameter influencing the severity of injury and possibility of death in pedestrian crashes. A collision damage mitigation braking system (CDMBS) using a sensor to detect pedestrians could be effective for reducing the vehicle/pedestrian impact velocity. Currently in Japan, cars equipped with the CDMBS also have vision sensors such as a stereo camera for pedestrian detection. However, the ability of vision sensors in production cars to properly detect pedestrians has not yet been established. The effect of reducing impact velocity on the pedestrian injury risk has also not been determined. The first objective of this study is to evaluate the performance of the CDMBS in detecting pedestrians when it is installed in production cars. The second objective of this study is to evaluate the effect of reducing impact velocity on mitigating pedestrian injury. Firstly, impact experiments were performed using a car with the CDMBS in which the car collided with a pedestrian surrogate. In these tests, the velocity was chosen for the various test runs to be 20, 40 and 60 km/h, respectively, which were based on the velocity distribution in real-world pedestrian crashes. The results indicated that the impact velocity reduction ranged approximately from 10 to 15 km/h at the standing location of a pedestrian surrogate at both daytime and nighttime lighting conditions. These results show that the system has the potential to reduce pedestrian casualties from car-to-pedestrian contacts. Secondly, finite-element analyses were performed simulating vehicle-to- pedestrian impacts with the THUMS pedestrian models. The vehicle models selected for the study included a medium sedan

  3. The flash flood event in the catchment of the river Weisseritz (eastern Erzgebirge, Saxony) from 12.-14. August 2002 - meteorological and hydrological reasons, damage assesment and disaster managment

    Science.gov (United States)

    Goldberg, V.; Bernhofer, Ch.

    2003-04-01

    Between 12. and 14. August 2002 the region of eastern Erzgebirge (Saxony/Eastern Germany) was affected by the heaviest rainfall event recorded since beginning of the measuring period in 1883. The synoptic reason of this event was the advective precipitation due to the strong and very slowly shifting Vb-low "Ilse" combined with a noticeable topographic intensification by north-westerly winds. All stations in the catchment area of the river Weisseritz recorded new all-time records. E.g., at the meteorological station Zinnwald-Georgenfeld situated at the crest of eastern Erzgebirge a daily sum of 312 mm was measured for the 13. August. This value is close to the maximum physically possible rainfall. The intensive rainfall in the catchments of Rote Weisseritz and Wilde Weisseritz led to unexperienced heavy flash floods with large material transport and flow damages. The buffer effect of the existing dam systems was comparatively small because the reserved retaining capacity for flood protection was only about 20 percent of the total capacity. The reservoirs filled quickly due to the very high maximum inflow. So a long-time overflow of the dam system occurred with a maximum of about 300 cubic meters per second at the combined river Weisseritz through the cities of Freital and Dresden (This situation led, e.g., to the flooding of Central Railway Station in Dresden). This water flow is comparable with a medium flow rate of the river Elbe in Dresden, and it is about 300 times higher than the normal drain of the river Weisseritz in Freital! The material damages in the Weisseritz region account for several hundred millions EURO, and several causalties occurred. The damages of the University buildings in Tharandt (including one building of the Department of Meteorology) account for 15 millions EURO alone. The disaster management during the flood was not optimal. For many people, e.g. in Tharandt, there was neither an officially warning nor an organised rescue of movable goods

  4. Layered Fault Rocks Below the West Salton Detachment Fault (WSDF), CA Record Multiple Seismogenic? Slip Events and Transfer of Material to a Fault Core

    Science.gov (United States)

    Axen, G. J.; Luther, A. L.; Selverstone, J.; Mozley, P.

    2011-12-01

    -size distributions reflect constrained comminution and shear localization (slopes of ~3-3.5 on log-log plots of grain size vs. no. of grains > grain size). The LCs require episodic slip events that probably record dozens of seismic cycles. Foliation likely records post- or interseismic creep. Geometric complexities among the WSDF footwall splays presumably caused episodic dilation that allowed accumulation and folding of the LCs. Mechanical processes dominated over chemical processes. A key question is why the LCs apparently were stronger than the overlying granodiorite, leading to formation of new LC layers rather than significant reworking of older layers.

  5. Towards a Molecular Understanding of the Fanconi Anemia Core Complex

    Directory of Open Access Journals (Sweden)

    Charlotte Hodson

    2012-01-01

    Full Text Available Fanconi Anemia (FA is a genetic disorder characterized by the inability of patient cells to repair DNA damage caused by interstrand crosslinking agents. There are currently 14 verified FA genes, where mutation of any single gene prevents repair of DNA interstrand crosslinks (ICLs. The accumulation of ICL damage results in genome instability and patients having a high predisposition to cancers. The key event of the FA pathway is dependent on an eight-protein core complex (CC, required for the monoubiquitination of each member of the FANCD2-FANCI complex. Interestingly, the majority of patient mutations reside in the CC. The molecular mechanisms underlying the requirement for such a large complex to carry out a monoubiquitination event remain a mystery. This paper documents the extensive efforts of researchers so far to understand the molecular roles of the CC proteins with regard to its main function in the FA pathway, the monoubiquitination of FANCD2 and FANCI.

  6. Towards a Molecular Understanding of the Fanconi Anemia Core Complex

    Science.gov (United States)

    Hodson, Charlotte; Walden, Helen

    2012-01-01

    Fanconi Anemia (FA) is a genetic disorder characterized by the inability of patient cells to repair DNA damage caused by interstrand crosslinking agents. There are currently 14 verified FA genes, where mutation of any single gene prevents repair of DNA interstrand crosslinks (ICLs). The accumulation of ICL damage results in genome instability and patients having a high predisposition to cancers. The key event of the FA pathway is dependent on an eight-protein core complex (CC), required for the monoubiquitination of each member of the FANCD2-FANCI complex. Interestingly, the majority of patient mutations reside in the CC. The molecular mechanisms underlying the requirement for such a large complex to carry out a monoubiquitination event remain a mystery. This paper documents the extensive efforts of researchers so far to understand the molecular roles of the CC proteins with regard to its main function in the FA pathway, the monoubiquitination of FANCD2 and FANCI. PMID:22675617

  7. Windscale pile core surveys

    International Nuclear Information System (INIS)

    Curtis, R.F.; Mathews, R.F.

    1996-01-01

    The two Windscale Piles were closed down, defueled as far as possible and mothballed for thirty years following a fire in the core of Pile 1 in 1957 resulting from the spontaneous release of stored Wigner energy in the graphite moderator. Decommissioning of the reactors commenced in 1987 and has reached the stage where the condition of both cores needs to be determined. To this end, non-intrusive and intrusive surveys and sampling of the cores have been planned and partly implemented. The objectives for each Pile differ slightly. The location and quantity of fuel remaining in the damaged core of Pile 1 needed to be established, whereas the removal of all fuel from Pile 2 needed to be confirmed. In Pile 1, the possible existence of a void in the core is to be explored and in Pile 2, the level of Wigner energy remaining required to be quantified. Levels of radioactivity in both cores needed to be measured. The planning of the surveys is described including strategy, design, safety case preparation and the remote handling and viewing equipment required to carry out the inspection, sampling and monitoring work. The results from the completed non-intrusive survey of Pile 2 are summarised. They confirm that the core is empty and the graphite is in good condition. The survey of Pile 1 has just started. (UK)

  8. TMI-2 core examination

    International Nuclear Information System (INIS)

    Hobbins, R.R.; MacDonald, P.E.; Owen, D.E.

    1983-01-01

    The examination of the damaged core at the Three Mile Island Unit 2 (TMI-2) reactor is structured to address the following safety issues: fission product release, transport, and deposition; core coolability; containment integrity; and recriticality during severe accidents; as well as zircaloy cladding ballooning and oxidation during so-called design basis accidents. The numbers of TMI-2 components or samples to be examined, the priority of each examination, the safety issue addressed by each examination, the principal examination techniques to be employed, and the data to be obtained and the principal uses of the data are discussed in this paper

  9. TMI-2 core debris analysis

    International Nuclear Information System (INIS)

    Cook, B.A.; Carlson, E.R.

    1985-01-01

    One of the ongoing examination tasks for the damaged TMI-2 reactor is analysis of samples of debris obtained from the debris bed presently at the top of the core. This paper summarizes the results reported in the TMI-2 Core Debris Grab Sample Examination and Analysis Report, which will be available early in 1986. The sampling and analysis procedures are presented, and information is provided on the key results as they relate to the present core condition, peak temperatures during the transient, temperature history, chemical interactions, and core relocation. The results are then summarized

  10. Core catcher for nuclear reactor core meltdown containment

    International Nuclear Information System (INIS)

    Driscoll, M.J.; Bowman, F.L.

    1978-01-01

    A bed of graphite particles is placed beneath a nuclear reactor core outside the pressure vessel but within the containment building to catch the core debris in the event of failure of the emergency core cooling system. Spray cooling of the debris and graphite particles together with draining and flooding of coolant fluid of the graphite bed is provided to prevent debris slump-through to the bottom of the bed

  11. Overview of core disruptive accidents

    International Nuclear Information System (INIS)

    Marchaterre, J.F.

    1977-01-01

    An overview of the analysis of core-disruptive accidents is given. These analyses are for the purpose of understanding and predicting fast reactor behavior in severe low probability accident conditions, to establish the consequences of such conditions and to provide a basis for evaluating consequence limiting design features. The methods are used to analyze core-disruptive accidents from initiating event to complete core disruption, the effects of the accident on reactor structures and the resulting radiological consequences are described

  12. A time-dependent event tree technique for modelling recovery operations

    International Nuclear Information System (INIS)

    Kohut, P.; Fitzpatrick, R.

    1991-01-01

    The development of a simplified time dependent event tree methodology is presented. The technique is especially applicable to describe recovery operations in nuclear reactor accident scenarios initiated by support system failures. The event tree logic is constructed using time dependent top events combined with a damage function that contains information about the final state time behavior of the reactor core. Both the failure and the success states may be utilized for the analysis. The method is illustrated by modeling the loss of service water function with special emphasis on the RCP [reactor coolant pump] seal LOCA [loss of coolant accident] scenario. 5 refs., 2 figs., 2 tabs

  13. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2008-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  14. Transformer core

    NARCIS (Netherlands)

    Mehendale, A.; Hagedoorn, Wouter; Lötters, Joost Conrad

    2010-01-01

    A transformer core includes a stack of a plurality of planar core plates of a magnetically permeable material, which plates each consist of a first and a second sub-part that together enclose at least one opening. The sub-parts can be fitted together via contact faces that are located on either side

  15. TMI-2 core bore acquisition summary report

    International Nuclear Information System (INIS)

    Tolman, E.L.; Smith, R.P.; Martin, M.R.; McCardell, R.K.; Broughton, J.M.

    1986-09-01

    Core bore samples were obtained from the severely damaged TMI-2 core during July and August, 1986. A description of the TMI-2 core bore drilling unit used to obtain samples; a summary and discussion of the data from the ten core bore segments which were obtained; and the initial results of analysis and evaluation of these data are presented in this report. The impact of the major findings relative to our understanding of the accident scenario is also discussed

  16. Activity release from the damaged spent VVER-fuel during long-term wet storage

    Energy Technology Data Exchange (ETDEWEB)

    Slonszki, E.; Hozer, Z. [Hungarian Academy of Sciences, KFKI Atomic Energy Research Inst., Budapest (Hungary); Pinter, T.; Baracska Varju, I. [Nuclear Power Plant Paks, Paks (Hungary)

    2010-07-01

    An ex-core fuel damage incident took place at Unit 2 of Paks Nuclear Power Plant in Hungary on the 10{sup th} April 2003. After this event the damaged fuel assemblies were stored under water for four years. During wet storage a continuous activity release was observed. The evaluation of the measured activity concentration showed that the UO{sub 2} mass released from the fuel into the coolant was {approx} 1.8% of the total fuel mass. Furthermore this paper contains the calculation methods and the calculated activity release of the main analysed isotopes. (orig.)

  17. Activity release from the damaged spent VVER-fuel during long-term wet storage

    International Nuclear Information System (INIS)

    Slonszki, E.; Hozer, Z.; Pinter, T.; Baracska Varju, I.

    2010-01-01

    An ex-core fuel damage incident took place at Unit 2 of Paks Nuclear Power Plant in Hungary on the 10 th April 2003. After this event the damaged fuel assemblies were stored under water for four years. During wet storage a continuous activity release was observed. The evaluation of the measured activity concentration showed that the UO 2 mass released from the fuel into the coolant was ∼ 1.8% of the total fuel mass. Furthermore this paper contains the calculation methods and the calculated activity release of the main analysed isotopes. (orig.)

  18. Timing of the Three Mile Island Unit 2 core degradation as determined by forensic engineering

    International Nuclear Information System (INIS)

    Henrie, J.O.

    1988-01-01

    Unlike computer simulation of an event, forensic engineering is the evaluation of recorded data and damaged as well as surviving components after an event to determine progressive causes of the event. Such an evaluation of the 1979 Three Mile Island Unit 2 accident indicates that gas began accumulating in steam, generator A at 6:10, or 130 min into the accident and, therefore, fuel cladding ruptures and/or zirconium-water reactions began at that time. Zirconium oxidation/hydrogen generation rates were highest (∼70 kg of hydrogen per minute) during the core quench and collapse at 175 min. By 180 min, over 85% of the hydrogen generated by the zirconium-water reaction had been produced, and ∼400 kg of hydrogen had accumulated in the reactor coolant system. At that time, hydrogen concentrations at the steam/water interfaces in both steam generators approached 90%. By 203 min, the damaged reactor core had been reflooded and has not been uncovered since that time. Therefore, the core was completely under water at 225 min, when molten core material flowed into the lower head of the reactor vessel. 10 refs., 7 figs., 1 tab

  19. Core lifter

    Energy Technology Data Exchange (ETDEWEB)

    Pavlov, N G; Edel' man, Ya A

    1981-02-15

    A core lifter is suggested which contains a housing, core-clamping elements installed in the housing depressions in the form of semirings with projections on the outer surface restricting the rotation of the semirings in the housing depressions. In order to improve the strength and reliability of the core lifter, the semirings have a variable transverse section formed from the outside by the surface of the rotation body of the inner arc of the semiring aroung the rotation axis and from the inner a cylindrical surface which is concentric to the outer arc of the semiring. The core-clamping elements made in this manner have the possibility of freely rotating in the housing depressions under their own weight and from contact with the core sample. These semirings do not have weakened sections, have sufficient strength, are inserted into the limited ring section of the housing of the core lifter without reduction in its through opening and this improve the reliability of the core lifter in operation.

  20. Scale interactions in economics: application to the evaluation of the economic damages of climatic change and of extreme events; Interactions d'echelles en economie: application a l'evaluation des dommages economiques du changement climatique et des evenements extremes

    Energy Technology Data Exchange (ETDEWEB)

    Hallegatte, S

    2005-06-15

    Growth models, which neglect economic disequilibria, considered as temporary, are in general used to evaluate the damaging effects generated by climatic change. This work shows, through a series of modeling experiences, the importance of disequilibria and of endogenous variability of economy in the evaluation of damages due to extreme events and climatic change. It demonstrates the impossibility to separate the evaluation of damages from the representation of growth and of economic dynamics: the comfort losses will depend on both the nature and intensity of impacts and on the dynamics and situation of the economy to which they will apply. Thus, the uncertainties about the damaging effects of future climatic changes come from both scientific uncertainties and from uncertainties about the future organization of our economies. (J.S.)

  1. Probabilistic risk assessment (PRA) on the effectiveness of a core rescue system (SSN) for PWRs

    International Nuclear Information System (INIS)

    Petrangeli, G.; Valeri, A.

    1983-01-01

    Safety systems for the prevention of LWR core severe damage have recently been studied, which are based on automatic primary system depressurization and on borated water injection by low pressure accumulators. These systems have been named Core Rescue System (SSN). The present study evaluates the reduction in core melt probability brought about by the installation of a SSN system on the RSS (WASH 1400) PWR plant (Surry 1). The calculated result is a core melt probability reduction factor of about 250. Taking into account the possible effect of external or internal unknown events of negligible, yet undefined, probability it is concluded that a SSN system can make a plant ten times safer. The first part of a review report by Prof. N.C.Rasmussen, MIT, dealing with general comment, is attached

  2. Testing of the fuel element - radiation damage of the construction materials of the fuel element and reactor core; Ispitivanje gorivnog elementa - radijaciono ostecenje konstrukcionih materijala gorivnog elementa i jezgra reaktora

    Energy Technology Data Exchange (ETDEWEB)

    Stefanovic, V [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Yugoslavia)

    1965-11-15

    This report covers the following: review of present radiation damage testing of stainless steels and zircaloy-2 used in heavy water reactors; plan of experiments for irradiation of of these materials.

  3. Reactor core

    International Nuclear Information System (INIS)

    Azekura, Kazuo; Kurihara, Kunitoshi.

    1992-01-01

    In a BWR type reactor, a great number of pipes (spectral shift pipes) are disposed in the reactor core. Moderators having a small moderating cross section (heavy water) are circulated in the spectral shift pipes to suppress the excess reactivity while increasing the conversion ratio at an initial stage of the operation cycle. After the intermediate stage of the operation cycle in which the reactor core reactivity is lowered, reactivity is increased by circulating moderators having a great moderating cross section (light water) to extend the taken up burnup degree. Further, neutron absorbers such as boron are mixed to the moderator in the spectral shift pipe to control the concentration thereof. With such a constitution, control rods and driving mechanisms are no more necessary, to simplify the structure of the reactor core. This can increase the fuel conversion ratio and control great excess reactivity. Accordingly, a nuclear reactor core of high conversion and high burnup degree can be attained. (I.N.)

  4. Ice Cores

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Records of past temperature, precipitation, atmospheric trace gases, and other aspects of climate and environment derived from ice cores drilled on glaciers and ice...

  5. Overview of results and perspectives from the Shoreham major common-cause initiating events study

    International Nuclear Information System (INIS)

    Joksimovich, V.; Orvis, D.D.; Paccione, R.J.

    1986-01-01

    This study represents the continuation of a large effort by LILCO to fully understand the potential hazards posed by future operation of the Shoreham Nuclear Power Stations (SNPS). The Shoreham Probabilistic Risk Assessment, a level 3 PRA without external events, provided a characterization of the accident sequences that could leave the core in a condition in which it would be vulnerable to severe damage if further mitigating actions were not taken. It estimated the frequency and magnitude of the potential radioactivity releases associated with such sequences. The study was limited to accident sequences initiated by so called internal events to the plant including a loss of offsite power. It also characterized the public risk associated with those accident sequences. The ''Major Common-Cause Initiating Events Study'' (MCCI) for the Shoreham plant was performed to obtain insights into the plant's susceptibility to, and inherent defenses against, certain MCCIs. Major common-cause initiating events are occurrences which have the potential to initiate a plant transient or LOCA and, also, damage one or more plant systems needed to mitigate the effects of a transient or LOCA. The scope of the MCCI study included detailed analyses of seismic events and fires through the severe core damage and bounding analyses of aircraft crashes, windstorms, turbine missiles and release of hazardous materials near the plant

  6. Validation of the mortality prediction equation for damage control ...

    African Journals Online (AJOL)

    , preoperative lowest pH and lowest core body temperature to derive an equation for the purpose of predicting mortality in damage control surgery. It was shown to reliably predict death despite damage control surgery. The equation derivation ...

  7. Tort Damages

    NARCIS (Netherlands)

    L.T. Visscher (Louis)

    2008-01-01

    textabstractAbstract: In this Chapter, I provide an overview of Law and Economics literature regarding tort damages. Where necessary, attention is also spent to rules of tort liability. Both types of rules provide behavioral incentives to both injurers and victims, with respect to their level of

  8. Probabilistic safety analysis for fire events for the NPP Isar 2

    International Nuclear Information System (INIS)

    Schmaltz, H.; Hristodulidis, A.

    2007-01-01

    The 'Probabilistic Safety Analysis for Fire Events' (Fire-PSA KKI2) for the NPP Isar 2 was performed in addition to the PSA for full power operation and considers all possible events which can be initiated due to a fire. The aim of the plant specific Fire-PSA was to perform a quantitative assessment of fire events during full power operation, which is state of the art. Based on simplistic assumptions referring to the fire induced failures, the influence of system- and component-failures on the frequency of the core damage states was analysed. The Fire-PSA considers events, which will result due to fire-induced failures of equipment on the one hand in a SCRAM and on the other hand in events, which will not have direct operational effects but because of the fire-induced failure of safety related installations the plant will be shut down as a precautionary measure. These events are considered because they may have a not negligible influence on the frequency of core damage states in case of failures during the plant shut down because of the reduced redundancy of safety related systems. (orig.)

  9. Reactor core

    International Nuclear Information System (INIS)

    Matsuura, Tetsuaki; Nomura, Teiji; Tokunaga, Kensuke; Okuda, Shin-ichi

    1990-01-01

    Fuel assemblies in the portions where the gradient of fast neutron fluxes between two opposing faces of a channel box is great are kept loaded at the outermost peripheral position of the reactor core also in the second operation cycle in the order to prevent interference between a control rod and the channel box due to bending deformation of the channel box. Further, the fuel assemblies in the second row from the outer most periphery in the first operation cycle are also kept loaded at the second row in the second operation cycle. Since the gradient of the fast neutrons in the reactor core is especially great at the outer circumference of the reactor core, the channel box at the outer circumference is bent such that the surface facing to the center of the reactor core is convexed and the channel box in the second row is also bent to the identical direction, the insertion of the control rod is not interfered. Further, if the positions for the fuels at the outermost periphery and the fuels in the second row are not altered in the second operation cycle, the gaps are not reduced to prevent the interference between the control rod and the channel box. (N.H.)

  10. Pulsed laser damage to optical fibers

    International Nuclear Information System (INIS)

    Allison, S.W.; Gillies, G.T.; Magnuson, D.W.; Pagano, T.S.

    1985-01-01

    This paper describes some observations of pulsed laser damage to optical fibers with emphasis on a damage mode characterized as a linear fracture along the outer core of a fiber. Damage threshold data are presented which illustrate the effects of the focusing lens, end-surface preparation, and type of fiber. An explanation based on fiber-beam misalignment is given and is illustrated by a simple experiment and ray trace

  11. Earthquake damage to underground facilities

    International Nuclear Information System (INIS)

    Pratt, H.R.; Hustrulid, W.A.; Stephenson, D.E.

    1978-11-01

    The potential seismic risk for an underground nuclear waste repository will be one of the considerations in evaluating its ultimate location. However, the risk to subsurface facilities cannot be judged by applying intensity ratings derived from the surface effects of an earthquake. A literature review and analysis were performed to document the damage and non-damage due to earthquakes to underground facilities. Damage from earthquakes to tunnels, s, and wells and damage (rock bursts) from mining operations were investigated. Damage from documented nuclear events was also included in the study where applicable. There are very few data on damage in the subsurface due to earthquakes. This fact itself attests to the lessened effect of earthquakes in the subsurface because mines exist in areas where strong earthquakes have done extensive surface damage. More damage is reported in shallow tunnels near the surface than in deep mines. In mines and tunnels, large displacements occur primarily along pre-existing faults and fractures or at the surface entrance to these facilities.Data indicate vertical structures such as wells and shafts are less susceptible to damage than surface facilities. More analysis is required before seismic criteria can be formulated for the siting of a nuclear waste repository

  12. War damages and reconstruction of Peruca dam

    International Nuclear Information System (INIS)

    Nonveiller, E.; Sever, Z.

    1999-01-01

    The paper describes the heavy damages caused by blasting in the Peruca rockfill dam in Croatia in January 1993. Complete collapse of the dam by overtopping was prevented through quick action of the dam owner by dumping clayey gravel on the lowest sections of the dam crest and opening the bottom outlet of the reservoir, thus efficiently lowering the water level. After the damages were sufficiently established and alternatives for restoration of the dam were evaluated, it was decided to construct a diaphragm wall through the damaged core in the central dam part as the impermeable dam element and to rebuild the central clay core at the dam abutments. Reconstruction works are described

  13. Quantification of risk considering external events on the change of allowed outage time and the preventive maintenance during power operation

    Energy Technology Data Exchange (ETDEWEB)

    Kang, D. J.; Kim, K. Y.; Yang, J. E

    2001-03-01

    In this study, for the major safety systems of Ulchin Units 3/4, we quantify the risk on the change of AOT and the PM during power operation to identify the effects on the results of external events PSA when nuclear power plant changes such as allowed outage time are requested. The systems for which the risks on the change of allowed outage time are quantified are High Pressure Safety Injection System (HPSIS), Containment Spray System (CSS), and Emergency Diesel Generator (EDG). The systems for which the risks on the PM during power operation are Low Pressure Safety Injection System (LPSIS), CSS, EDG, Essential Service Water System (ESWS). Following conclusions can be obtained through this study: 1)The increase of core damage frequency ({delta}CDF) on the change of AOT and the conditional core damage probability (CCDP) on the on-line PM of each system are differently quantified according to the cases of considering only internal events or only external events. . 2)It is expected that the quantification of risk including internal and external events is advantageous for the licensee of NPP if the regulatory acceptance criteria for the technical specification changes are relatively set up. However, it is expected to be disadvantageous for the licensee if the acceptance criteria are absolutely set up. 3)It is expected that the conduction on the quantification of only a fire event is sufficient when the quantification of external events PSA model is required for the plant changes of Korea Standard NPPs. 4)It is expected that the quantification of the increase of core damage frequency and the incremental conditional core damage probability on technical specification changes are not needed if the quantification results of those considering only internal events are below regulatory acceptance criteria and the external events PSA results are not greatly affected by the system availability. However, it is expected that the quantification of risk considering external events

  14. Quantification of risk considering external events on the change of allowed outage time and the preventive maintenance during power operation

    International Nuclear Information System (INIS)

    Kang, D. J.; Kim, K. Y.; Yang, J. E.

    2001-03-01

    In this study, for the major safety systems of Ulchin Units 3/4, we quantify the risk on the change of AOT and the PM during power operation to identify the effects on the results of external events PSA when nuclear power plant changes such as allowed outage time are requested. The systems for which the risks on the change of allowed outage time are quantified are High Pressure Safety Injection System (HPSIS), Containment Spray System (CSS), and Emergency Diesel Generator (EDG). The systems for which the risks on the PM during power operation are Low Pressure Safety Injection System (LPSIS), CSS, EDG, Essential Service Water System (ESWS). Following conclusions can be obtained through this study: 1)The increase of core damage frequency (ΔCDF) on the change of AOT and the conditional core damage probability (CCDP) on the on-line PM of each system are differently quantified according to the cases of considering only internal events or only external events. . 2)It is expected that the quantification of risk including internal and external events is advantageous for the licensee of NPP if the regulatory acceptance criteria for the technical specification changes are relatively set up. However, it is expected to be disadvantageous for the licensee if the acceptance criteria are absolutely set up. 3)It is expected that the conduction on the quantification of only a fire event is sufficient when the quantification of external events PSA model is required for the plant changes of Korea Standard NPPs. 4)It is expected that the quantification of the increase of core damage frequency and the incremental conditional core damage probability on technical specification changes are not needed if the quantification results of those considering only internal events are below regulatory acceptance criteria and the external events PSA results are not greatly affected by the system availability. However, it is expected that the quantification of risk considering external events on

  15. DNA damage in neurodegenerative diseases

    Energy Technology Data Exchange (ETDEWEB)

    Coppedè, Fabio, E-mail: fabio.coppede@med.unipi.it; Migliore, Lucia, E-mail: lucia.migliore@med.unipi.it

    2015-06-15

    Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

  16. DNA damage in neurodegenerative diseases

    International Nuclear Information System (INIS)

    Coppedè, Fabio; Migliore, Lucia

    2015-01-01

    Highlights: • Oxidative DNA damage is one of the earliest detectable events in the neurodegenerative process. • The mitochondrial DNA is more vulnerable to oxidative attack than the nuclear DNA. • Cytogenetic damage has been largely documented in Alzheimer's disease patients. • The question of whether DNA damage is cause or consequence of neurodegeneration is still open. • Increasing evidence links DNA damage and repair with epigenetic phenomena. - Abstract: Following the observation of increased oxidative DNA damage in nuclear and mitochondrial DNA extracted from post-mortem brain regions of patients affected by neurodegenerative diseases, the last years of the previous century and the first decade of the present one have been largely dedicated to the search of markers of DNA damage in neuronal samples and peripheral tissues of patients in early, intermediate or late stages of neurodegeneration. Those studies allowed to demonstrate that oxidative DNA damage is one of the earliest detectable events in neurodegeneration, but also revealed cytogenetic damage in neurodegenerative conditions, such as for example a tendency towards chromosome 21 malsegregation in Alzheimer's disease. As it happens for many neurodegenerative risk factors the question of whether DNA damage is cause or consequence of the neurodegenerative process is still open, and probably both is true. The research interest in markers of oxidative stress was shifted, in recent years, towards the search of epigenetic biomarkers of neurodegenerative disorders, following the accumulating evidence of a substantial contribution of epigenetic mechanisms to learning, memory processes, behavioural disorders and neurodegeneration. Increasing evidence is however linking DNA damage and repair with epigenetic phenomena, thereby opening the way to a very attractive and timely research topic in neurodegenerative diseases. We will address those issues in the context of Alzheimer's disease

  17. A Method to Quantify Plant Availability and Initiating Event Frequency Using a Large Event Tree, Small Fault Tree Model

    International Nuclear Information System (INIS)

    Kee, Ernest J.; Sun, Alice; Rodgers, Shawn; Popova, ElmiraV; Nelson, Paul; Moiseytseva, Vera; Wang, Eric

    2006-01-01

    South Texas Project uses a large fault tree to produce scenarios (minimal cut sets) used in quantification of plant availability and event frequency predictions. On the other hand, the South Texas Project probabilistic risk assessment model uses a large event tree, small fault tree for quantifying core damage and radioactive release frequency predictions. The South Texas Project is converting its availability and event frequency model to use a large event tree, small fault in an effort to streamline application support and to provide additional detail in results. The availability and event frequency model as well as the applications it supports (maintenance and operational risk management, system engineering health assessment, preventive maintenance optimization, and RIAM) are briefly described. A methodology to perform availability modeling in a large event tree, small fault tree framework is described in detail. How the methodology can be used to support South Texas Project maintenance and operations risk management is described in detail. Differences with other fault tree methods and other recently proposed methods are discussed in detail. While the methods described are novel to the South Texas Project Risk Management program and to large event tree, small fault tree models, concepts in the area of application support and availability modeling have wider applicability to the industry. (authors)

  18. Core BPEL

    DEFF Research Database (Denmark)

    Hallwyl, Tim; Højsgaard, Espen

    The Web Services Business Process Execution Language (WS-BPEL) is a language for expressing business process behaviour based on web services. The language is intentionally not minimal but provides a rich set of constructs, allows omission of constructs by relying on defaults, and supports language......, does not allow omissions, and does not contain ignorable elements. We do so by identifying syntactic sugar, including default values, and ignorable elements in WS-BPEL. The analysis results in a translation from the full language to the core subset. Thus, we reduce the effort needed for working...

  19. The Intertwined Roles of DNA Damage and Transcription

    OpenAIRE

    Di Palo, Giacomo

    2016-01-01

    DNA damage and transcription are two interconnected events. Transcription can induce damage and scheduled DNA damage can be required for transcription. Here, we analyzed genome-wide distribution of 8oxodG-marked oxidative DNA damage obtained by OxiDIP-Seq, and we found a correlation with transcription of protein coding genes.

  20. Estimation of initiating event frequency for external flood events by extreme value theorem

    International Nuclear Information System (INIS)

    Chowdhury, Sourajyoti; Ganguly, Rimpi; Hari, Vibha

    2017-01-01

    External flood is an important common cause initiating event in nuclear power plants (NPPs). It may potentially lead to severe core damage (SCD) by first causing the failure of the systems required for maintaining the heat sinks and then by contributing to failures of engineered systems designed to mitigate such failures. The sample NPP taken here is twin 220 MWe Indian standard pressurized heavy water reactor (PHWR) situated inland. A comprehensive in-house Level-1 internal event PSA for full power had already been performed. External flood assessment was further conducted in area of external hazard risk assessment in response to post-Fukushima measures taken in nuclear industries. The present paper describes the methodology to calculate initiating event (IE) frequency for external flood events for the sample inland Indian NPP. General extreme value (GEV) theory based on maximum likelihood method (MLM) and order statistics approach (OSA) is used to analyse the rainfall data for the site. Thousand-year return level and necessary return periods for extreme rainfall are evaluated. These results along with plant-specific topographical calculations quantitatively establish that external flooding resulting from upstream dam break, river flooding and heavy rainfall (flash flood) would be unlikely for the sample NPP in consideration.

  1. Core baffle for nuclear reactors

    International Nuclear Information System (INIS)

    Machado, O.J.; Berringer, R.T.

    1977-01-01

    The invention concerns the design of the core of a LWR with a large number of fuel assemblies formed by fuel rods and kept in position by spacer grids. According to the invention, at the level of the spacer grids match plates are mounted with openings so the flow of coolant directed upwards will not be obstructed and a parallel bypass will be obtained in the space between the core barrel and the baffle plates. In case of an accident, this configuration reduces or avoids damage from overpressure reactions. (HP) [de

  2. Ice Sheets & Ice Cores

    DEFF Research Database (Denmark)

    Mikkelsen, Troels Bøgeholm

    Since the discovery of the Ice Ages it has been evident that Earth’s climate is liable to undergo dramatic changes. The previous climatic period known as the Last Glacial saw large oscillations in the extent of ice sheets covering the Northern hemisphere. Understanding these oscillations known....... The first part concerns time series analysis of ice core data obtained from the Greenland Ice Sheet. We analyze parts of the time series where DO-events occur using the so-called transfer operator and compare the results with time series from a simple model capable of switching by either undergoing...

  3. Ice cores and palaeoclimate

    International Nuclear Information System (INIS)

    Krogh Andersen, K.; Ditlevsen, P.; Steffensen, J.P.

    2001-01-01

    Ice cores from Greenland give testimony of a highly variable climate during the last glacial period. Dramatic climate warmings of 15 to 25 deg. C for the annual average temperature in less than a human lifetime have been documented. Several questions arise: Why is the Holocene so stable? Is climatic instability only a property of glacial periods? What is the mechanism behind the sudden climate changes? Are the increased temperatures in the past century man-made? And what happens in the future? The ice core community tries to attack some of these problems. The NGRIP ice core currently being drilled is analysed in very high detail, allowing for a very precise dating of climate events. It will be possible to study some of the fast changes on a year by year basis and from this we expect to find clues to the sequence of events during rapid changes. New techniques are hoped to allow for detection of annual layers as far back as 100,000 years and thus a much improved time scale over past climate changes. It is also hoped to find ice from the Eemian period. If the Eemian layers confirm the GRIP sequence, the Eemian was actually climatically unstable just as the glacial period. This would mean that the stability of the Holocene is unique. It would also mean, that if human made global warming indeed occurs, we could jeopardize the Holocene stability and create an unstable 'Eemian situation' which ultimately could start an ice age. Currenlty mankind is changing the composition of the atmosphere. Ice cores document significant increases in greenhouse gases, and due to increased emissions of sulfuric and nitric acid from fossil fuel burning, combustion engines and agriculture, modern Greenland snow is 3 - 5 times more acidic than pre-industrial snow (Mayewski et al., 1986). However, the magnitude and abruptness of the temperature changes of the past century do not exceed the magnitude of natural variability. It is from the ice core perspective thus not possible to attribute the

  4. A retrospective look on plant events for prospective affirmation of nuclear safety

    International Nuclear Information System (INIS)

    Koshy, Thomas; Khamis, Ibrahim

    2014-01-01

    The nuclear industry continues to rise above the challenges resulting from major plant events around the world. It is important to study the significant events, develop solutions to overcome the vulnerabilities identified, and retain the lessons while technology evolves to the next generation. The historical Station-Black-Out needs to be examined further in a new dimension in the light of 'Fukushima type' events where normal AC power recovery in a reasonable period was not practical. The plants would need to incorporate diversity in emergency core cooling to account for a condition that inhibits electrical energy as a source of motive power. An electrical event in Sweden that propagated from an electrical switchyard resulted in two core cooling divisions disabled and consequently exacerbating the plant condition by opening the relief system for reactor coolant system and that significantly increased the probability for core damage. A minor spark in an electronic control system card in a US plant caused inadvertent emergency core cooling and disabled the Control Room Operators' capability to intervene and prevent the primary loop from getting completely filled. A renewed assessment is needed to address the following areas for advancing reactor safety in the new evolving generation of plants to advance safety from the event lessons of the past. - Evaluate the diversity in core cooling systems following loss of all AC power onsite - Confirm independence in Reactor Trip, Depressurization and Core and Containment cooling systems for sensors, power supplies and actuation systems - Evaluate the suitability of logic/control system failure mode resulting from power supply failures in instrument channels and/or divisions (Conduct Failure Mode and Effects Analysis for system, power supplies and components). (authors)

  5. Support tube of in-core instruments

    International Nuclear Information System (INIS)

    Suzumura, Takeshi; Saito, Shozo; Yasuda, Tetsuo; Shirosaki, Kiyotaka.

    1975-01-01

    Object: To permit satisfactory output measurement by preventing the bending of a in-core instrument tube within a reactor due to vibrations by means of a spring and thereby preventing mechanical damage of an adjacent fuel channel box. Structure: At a corner of a channel box of a fuel assembly, a in-core instrument tube is arranged along a channel box and has its surface provided with a plurality of removable leaf springs arranged in the direction of axis of the in-core instrument tube and each having an arcular tip. Thus, when the in-core instrument tube is inserted into the reactor, the arcular tip portions of the leaf springs are brought into plane contact with the corner of the channel box so that the in-core instrument tube is elastically supported on the channel box. Thus, there is no possibility of causing damage to the adjacent fuel channel box. (Kamimura, M.)

  6. Collapsing stellar cores and supernovae

    Energy Technology Data Exchange (ETDEWEB)

    Epstein, R J [Nordisk Inst. for Teoretisk Atomfysik, Copenhagen (Denmark); Noorgaard, H [Nordisk Inst. for Teoretisk Atomfysik, Copenhagen (Denmark); Chicago Univ., IL (USA). Enrico Fermi Inst.); Bond, J R [Niels Bohr Institutet, Copenhagen (Denmark); California Inst. of Tech., Pasadena (USA). W.K. Kellogg Radiation Lab.)

    1979-05-01

    The evolution of a stellar core is studied during its final quasi-hydrostatic contraction. The core structure and the (poorly known) properties of neutron rich matter are parametrized to include most plausible cases. It is found that the density-temperature trajectory of the material in the central part of the core (the core-center) is insensitive to nearly all reasonable parameter variations. The central density at the onset of the dynamic phase of the collapse (when the core-center begins to fall away from the rest of the star) and the fraction of the emitted neutrinos which are trapped in the collapsing core-center depend quite sensitively on the properties of neutron rich matter. We estimate that the amount of energy Ecm which is imparted to the core-mantle by the neutrinos which escape from the imploded core-center can span a large range of values. For plausible choices of nuclear and model parameters Ecm can be large enough to yield a supernova event.

  7. Probabilistic analysis of external events with focus on the Fukushima event

    International Nuclear Information System (INIS)

    Kollasko, Heiko; Jockenhoevel-Barttfeld, Mariana; Klapp, Ulrich

    2014-01-01

    External hazards are those natural or man-made hazards to a site and facilities that are originated externally to both the site and its processes, i.e. the duty holder may have very little or no control over the hazard. External hazards can have the potential of causing initiating events at the plant, typically transients like e.g., loss of offsite power. Simultaneously, external events may affect safety systems required to control the initiating event and, where applicable, also back-up systems implemented for risk-reduction. The plant safety may especially be threatened when loads from external hazards exceed the load assumptions considered in the design of safety-related systems, structures and components. Another potential threat is given by hazards inducing initiating events not considered in the safety demonstration otherwise. An example is loss of offsite power combined with prolonged plant isolation. Offsite support, e.g., delivery of diesel fuel oil, usually credited in the deterministic safety analysis may not be possible in this case. As the Fukushima events have shown, the biggest threat is likely given by hazards inducing both effects. Such hazards may well be dominant risk contributors even if their return period is very high. In order to identify relevant external hazards for a certain Nuclear Power Plant (NPP) location, a site specific screening analysis is performed, both for single events and for combinations of external events. As a result of the screening analysis, risk significant and therefore relevant (screened-in) single external events and combinations of them are identified for a site. The screened-in events are further considered in a detailed event tree analysis in the frame of the Probabilistic Safety Analysis (PSA) to calculate the core damage/large release frequency resulting from each relevant external event or from each relevant combination. Screening analyses of external events performed at AREVA are based on the approach provided

  8. Development of a parametric containment event tree model for a severe BWR accident

    Energy Technology Data Exchange (ETDEWEB)

    Okkonen, T [OTO-Consulting Ay, Helsinki (Finland)

    1995-04-01

    A containment event tree (CET) is built for analysis of severe accidents at the TVO boiling water reactor (BWR) units. Parametric models of severe accident progression and fission product behaviour are developed and integrated in order to construct a compact and self-contained Level 2 PSA model. The model can be easily updated to correspond to new research results. The analyses of the study are limited to severe accidents starting from full-power operation and leading to core melting, and are focused mainly on the use and effects of the dedicated severe accident management (SAM) systems. Severe accident progression from eight plant damage states (PDS), involving different pre-core-damage accident evolution, is examined, but the inclusion of their relative or absolute probabilities, by integration with Level 1, is deferred to integral safety assessments. (33 refs., 5 figs., 7 tabs.).

  9. Assessment of accident energetics in LMFBR core-disruptive accidents

    International Nuclear Information System (INIS)

    Fauske, H.K.

    1977-01-01

    An assessment of accident energetics in LMFBR core-disruptive accidents is given with emphasis on the generic issues of energetic recriticality and energetic fuel-coolant interaction events. Application of a few general behavior principles to the oxide-fueled system suggests that such events are highly unlikely following a postulated core meltdown event

  10. Event Investigation

    International Nuclear Information System (INIS)

    Korosec, D.

    2000-01-01

    The events in the nuclear industry are investigated from the license point of view and from the regulatory side too. It is well known the importance of the event investigation. One of the main goals of such investigation is to prevent the circumstances leading to the event and the consequences of the event. The protection of the nuclear workers against nuclear hazard, and the protection of general public against dangerous effects of an event could be achieved by systematic approach to the event investigation. Both, the nuclear safety regulatory body and the licensee shall ensure that operational significant events are investigated in a systematic and technically sound manner to gather information pertaining to the probable causes of the event. One of the results should be appropriate feedback regarding the lessons of the experience to the regulatory body, nuclear industry and general public. In the present paper a general description of systematic approach to the event investigation is presented. The systematic approach to the event investigation works best where cooperation is present among the different divisions of the nuclear facility or regulatory body. By involving management and supervisors the safety office can usually improve their efforts in the whole process. The end result shall be a program which serves to prevent events and reduce the time and efforts solving the root cause which initiated each event. Selection of the proper method for the investigation and an adequate review of the findings and conclusions lead to the higher level of the overall nuclear safety. (author)

  11. Irradiation damage

    Energy Technology Data Exchange (ETDEWEB)

    Howe, L.M

    2000-07-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization.

  12. Irradiation damage

    International Nuclear Information System (INIS)

    Howe, L.M.

    2000-01-01

    There is considerable interest in irradiation effects in intermetallic compounds from both the applied and fundamental aspects. Initially, this interest was associated mainly with nuclear reactor programs but it now extends to the fields of ion-beam modification of metals, behaviour of amorphous materials, ion-beam processing of electronic materials, and ion-beam simulations of various kinds. The field of irradiation damage in intermetallic compounds is rapidly expanding, and no attempt will be made in this chapter to cover all of the various aspects. Instead, attention will be focused on some specific areas and, hopefully, through these, some insight will be given into the physical processes involved, the present state of our knowledge, and the challenge of obtaining more comprehensive understanding in the future. The specific areas that will be covered are: point defects in intermetallic compounds; irradiation-enhanced ordering and irradiation-induced disordering of ordered alloys; irradiation-induced amorphization

  13. Safety assessment of the advanced CANDU reactor in postulated LOCA/LOECC events

    International Nuclear Information System (INIS)

    Hazen Hezhi Fan; Zoran Bilanovic

    2005-01-01

    The Advanced CANDU Reactor TM (ACR TM ) retains the proven strengths and features of CANDU reactors, and incorporates innovative new features and state-of-the-art technology. In addition to the enhanced emergency core cooling system, the reserve water system is designed to be available to inject reserve water by gravity into the reactor inlet headers after a postulated loss-of-coolant accident (LOCA). To assist in the ACR design and analysis of beyond the design basis events, simulations are needed to demonstrate the effectiveness of these two independent systems on core cooling, and to assess the consequences of the postulated accident coincident with the impairment of either of the two systems. The current paper is subject to an assessment of a postulated large LOCA coincident with loss of the emergency core cooling (LOECC) system. A postulated LOCA/LOECC has very low probability, in the range usually associated with severe core damage events. However, in the CANDU design, including ACR, the presence of moderator water surrounding the fuel channels acts as an effective heat sink, together with other safety features, to prevents severe core damage following a postulated LOCA/LOECC. Therefore, it is possible to analyse LOCA/LOECC using the same deterministic tools that are used for analysis of events with much higher frequencies, in the design basis event range. The assessment is conducted based on the current ACR-700 design. However, the analysis methodology, scope, computer tools, and the results in principle, are applicable to larger ACR designs. This assessment includes system (circuit), fuel channel, and fuel analyses. Some assessment results are needed in subsequent moderator analysis and containment analysis. In the assessment, several simulations were performed to analyse the full circuit and individual fuel channel transient behaviours, as well as the fission product release behaviour. The assessment has captured the key responses of the reactor heat

  14. Defense-in-depth approach against a beyond design basis event

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, H., E-mail: Hoa.hoang@ge.com [GE Hitachi Nuclear Energy, 1989 Little Orchard St., 95125 San Jose, California (United States)

    2013-10-15

    The US industry, with the approval of the Nuclear Regulatory Commission, is promoting an approach to add diverse and flexible mitigation strategies, or Flex, that will increase the defense-in-depth capability for the nuclear power plants in the event of beyond design basis event, such as at the Fukushima Dai-ichi station. The objective of Flex is to establish and indefinite coping capability to prevent damage to the fuel in the core and spent fuel pool, and to maintain the containment function by utilizing installed equipment, on-site portable equipment and pre-staged off-site resources. This capability will address both an extended loss of all Ac power and a loss of ultimate heat sink which could arise following a design basis event with additional failures, and conditions from a beyond design basis event. (author)

  15. Defense-in-depth approach against a beyond design basis event

    International Nuclear Information System (INIS)

    Hoang, H.

    2013-10-01

    The US industry, with the approval of the Nuclear Regulatory Commission, is promoting an approach to add diverse and flexible mitigation strategies, or Flex, that will increase the defense-in-depth capability for the nuclear power plants in the event of beyond design basis event, such as at the Fukushima Dai-ichi station. The objective of Flex is to establish and indefinite coping capability to prevent damage to the fuel in the core and spent fuel pool, and to maintain the containment function by utilizing installed equipment, on-site portable equipment and pre-staged off-site resources. This capability will address both an extended loss of all Ac power and a loss of ultimate heat sink which could arise following a design basis event with additional failures, and conditions from a beyond design basis event. (author)

  16. TMI-2 core boring machine

    International Nuclear Information System (INIS)

    Croft, K.M.; Helbert, H.J.; Laney, W.M.

    1986-01-01

    An important and essential aspect of the TMI-2 defueling effort is to determine what occurred in the core region during the accident. Remote cameras and probes only portray a portion of the overall picture. What lies beneath the rubble bed and solidified sublayer is, as yet, unknown. This paper discusses the TMI-2 Core Boring Machine, which has been developed to drill into the damaged core of the TMI-2 reactor and extract stratified samples of the core. This machine, its unique support structure, positioning and leveling systems, and specially designed drill bits, combine to provide a unique mechanical system. In addition, the machine is controlled by a microprocessor; which actually controls the drilling operation, allowing relatively inexperienced operators to drill the core samples. A data acquisition system is data integral with the controlling system and collects data relative to system conditions and monitored parameters during drilling. Data obtained during the actual drilling operations are collected in a data base which will be used for actual mapping of the core region, identifying materials and stratification levels that are present

  17. Study of risk reduction by improving operation of reactor core isolation cooling system

    International Nuclear Information System (INIS)

    Watanabe, Yamato; Tazai, Ayuko; Yamagishi, Shohei; Muramatsu, Ken; Muta, Hitoshi

    2014-01-01

    The Fukushima Daiichi nuclear power plant fell into a station blackout (SBO) due to the earthquake and tsunami in which most of the core cooling systems were disabled. In the units 2 and 3, water injection to the core was performed only by water injection system with turbine driven pumps. In particular, it is inferred from observed plant parameters that the reactor core isolation cooling system (RCIC) continued its operation much longer than it was originally expected (8 hours). Since the preparation of safety measures did not work, the reactor core damaged. With a view to reduce risk of station blackout events in a BWR by accident management, this study investigated the efficacy of operation procedures that takes advantage of RCIC which can be operated with only equipment inside reactor building and does not require an AC power source. The efficacy was assessed in this study by two steps. The first step is a thermal hydraulic analysis with the RETRAN3D code to estimate the potential extension of duration of core cooling by RCIC and the second step is the estimation of time required for recovery of off-site power from experiences at nuclear power stations under the 3.11 earthquake. This study showed that it is possible to implement more reliable measures for accident termination and to greatly reduce the risk of SBO by the installation of accident management measures with use of RCIC for extension of core cooling under SBO conditions. (author)

  18. Damaged Skylab

    Science.gov (United States)

    1973-01-01

    The Saturn V vehicle, carrying the unmarned orbital workshop for the Skylab-1 mission, lifted off successfully and all systems performed normally. Sixty-three seconds into the flight, engineers in the operation support and control center saw an unexpected telemetry indication that signalled that damages occurred on one solar array and the micrometeoroid shield during the launch. The micrometeoroid shield, a thin protective cylinder surrounding the workshop protecting it from tiny space particles and the sun's scorching heat, ripped loose from its position around the workshop. This caused the loss of one solar wing and jammed the other. Still unoccupied, the Skylab was stricken with the loss of the heat shield and sunlight beat mercilessly on the lab's sensitive skin. Internal temperatures soared, rendering the station uninhabitable, threatening foods, medicines, films, and experiments. This image, taken during a fly-around inspection by the Skylab-2 crew, shows a crippled Skylab in orbit. The crew found their home in space to be in serious shape; the heat shield gone, one solar wing gone, and the other jammed. The Marshall Space Flight Center (MSFC) developed, tested, rehearsed, and approved three repair options. These options included a parasol sunshade and a twin-pole sunshade to restore the temperature inside the workshop, and a set of metal cutting tools to free the jammed solar panel.

  19. Structural damage

    International Nuclear Information System (INIS)

    Gray, R.E.; Bruhn, R.W.

    1992-01-01

    Virtually all structures show some signs of distress due to deterioration of the building components, to changed loads, or to changed support conditions. Changed support conditions result from ground movements. In mining regions many cases of structural distress are attributed to mining without considering alternative causes. This is particularly true of coal mining since it occurs under extensive areas. Coal mining is estimated to have already undermined more than eight million acres and may eventually undermine 40 million acres in the United States. Other nonmetal and metal underground mines impact much smaller areas. Although it is sometimes difficult, even with careful study, to identify the actual cause of damage, persons responsible for underground coal mining should at least be aware of possible causes of building stress other than mine subsidence. This paper presents information on distress to structures and briefly reviews a number of causes of ground movements other than subsidence: Mass movements, dissolution, erosion, frost action, shrinking and swelling, yield into excavations and compressibility

  20. Materials behaviour in PWRs core

    International Nuclear Information System (INIS)

    Barbu, A.; Massoud, J.P.

    2008-01-01

    Like in any industrial facility, the materials of PWR reactors are submitted to mechanical, thermal or chemical stresses during particularly long durations of operation: 40 years, and even 60 years. Materials closer to the nuclear fuel are submitted to intense bombardment of particles (mainly neutrons) coming from the nuclear reactions inside the core. In such conditions, the damages can be numerous and various: irradiation aging, thermal aging, friction wear, generalized corrosion, stress corrosion etc.. The understanding of the materials behaviour inside the cores of reactors in operation is a major concern for the nuclear industry and its long term forecast is a necessity. This article describes the main ways of materials degradation without and under irradiation, with the means used to foresee their behaviour using physics-based models. Content: 1 - structures, components and materials: structure materials, nuclear materials; 2 - main ways of degradation without irradiation: thermal aging, stress corrosion, wear; 3 - main ways of degradation under irradiation: microscopic damaging - point defects, dimensional alterations, evolution of mechanical characteristics under irradiation, irradiation-assisted stress corrosion cracking (IASCC), synergies; 4 - forecast of materials evolution under irradiation using physics-based models: primary damage - fast dynamics, primary damage annealing - slow kinetics microstructural evolution, impact of microstructural changes on the macroscopic behaviour, insight on modeling methods; 5 - materials change characterization techniques: microscopic techniques - direct defects observation, nuclear techniques using a particle beam, global measurements, mechanical characterizations; 6 - perspectives. (J.S.)

  1. Studies on WWER core diagnostics

    International Nuclear Information System (INIS)

    Lunin, G.L.; Mitin, V.I.; Bulavin, V.V.

    1987-01-01

    The reliability and safety of nuclear power plants have decisive meaning under the situation that nuclear power generation steadily increases, and among various measures aiming at ensuring the reliability and safety in the operation of nuclear power plants, the countermeasures for protecting reactor core, main process equipment and high pressure circuits from damage have the important role, and the monitoring of condition and the organization of forecast, which are carried out continuously or periodically during the operation of nuclear power stations using the diagnostic expert system specially developed for the purpose, are included in them. Such monitoring enables the early detection of mechanical damage, increase of vibration, defects caused during operation and so on in reactor cores and primary and secondary circuits, and the continuous watching of defect developments. Also boiling in a core is detected, the place of abnormality occurrence is identified, and the intensity and characteristics of boiling are determined, thus the occurrence of dangerous condition is prevented. The developments of an in-core monitoring system and noise diagnostic systems are reported. (Kako, I.)

  2. Initiating Event Analysis of a Lithium Fluoride Thorium Reactor

    Science.gov (United States)

    Geraci, Nicholas Charles

    The primary purpose of this study is to perform an Initiating Event Analysis for a Lithium Fluoride Thorium Reactor (LFTR) as the first step of a Probabilistic Safety Assessment (PSA). The major objective of the research is to compile a list of key initiating events capable of resulting in failure of safety systems and release of radioactive material from the LFTR. Due to the complex interactions between engineering design, component reliability and human reliability, probabilistic safety assessments are most useful when the scope is limited to a single reactor plant. Thus, this thesis will study the LFTR design proposed by Flibe Energy. An October 2015 Electric Power Research Institute report on the Flibe Energy LFTR asked "what-if?" questions of subject matter experts and compiled a list of key hazards with the most significant consequences to the safety or integrity of the LFTR. The potential exists for unforeseen hazards to pose additional risk for the LFTR, but the scope of this thesis is limited to evaluation of those key hazards already identified by Flibe Energy. These key hazards are the starting point for the Initiating Event Analysis performed in this thesis. Engineering evaluation and technical study of the plant using a literature review and comparison to reference technology revealed four hazards with high potential to cause reactor core damage. To determine the initiating events resulting in realization of these four hazards, reference was made to previous PSAs and existing NRC and EPRI initiating event lists. Finally, fault tree and event tree analyses were conducted, completing the logical classification of initiating events. Results are qualitative as opposed to quantitative due to the early stages of system design descriptions and lack of operating experience or data for the LFTR. In summary, this thesis analyzes initiating events using previous research and inductive and deductive reasoning through traditional risk management techniques to

  3. Acetylation dynamics of human nuclear proteins during the ionizing radiation-induced DNA damage response

    DEFF Research Database (Denmark)

    Bennetzen, Martin; Andersen, J.S.; Lasen, D.H.

    2013-01-01

    Genotoxic insults, such as ionizing radiation (IR), cause DNA damage that evokes a multifaceted cellular DNA damage response (DDR). DNA damage signaling events that control protein activity, subcellular localization, DNA binding, protein-protein interactions, etc. rely heavily on time...

  4. Event Modeling

    DEFF Research Database (Denmark)

    Bækgaard, Lars

    2001-01-01

    The purpose of this chapter is to discuss conceptual event modeling within a context of information modeling. Traditionally, information modeling has been concerned with the modeling of a universe of discourse in terms of information structures. However, most interesting universes of discourse...... are dynamic and we present a modeling approach that can be used to model such dynamics.We characterize events as both information objects and change agents (Bækgaard 1997). When viewed as information objects events are phenomena that can be observed and described. For example, borrow events in a library can...

  5. Wiring Damage Analyses for STS OV-103

    Science.gov (United States)

    Thomas, Walter, III

    2006-01-01

    This study investigated the Shuttle Program s belief that Space Transportation System (STS) wiring damage occurrences are random, that is, a constant occurrence rate. Using Problem Reporting and Corrective Action (PRACA)-derived data for STS Space Shuttle OV-103, wiring damage was observed to increase over the vehicle s life. Causal factors could include wiring physical deterioration, maintenance and inspection induced damage, and inspection process changes resulting in more damage events being reported. Induced damage effects cannot be resolved with existent data. Growth analysis (using Crow-AMSAA, or CA) resolved maintenance/inspection effects (e.g., heightened awareness) on all wire damages and indicated an overall increase since Challenger Return-to-Flight (RTF). An increasing failure or occurrence rate per flight cycle was seen for each wire damage mode; these (individual) rates were not affected by inspection process effects, within statistical error.

  6. Utilization of control rod drive (CRD) system for long term core cooling

    International Nuclear Information System (INIS)

    Huerta B, A.

    1991-01-01

    In this paper we consider an application of Probabilistic Risk Assessment (PRA) to risk management. Foreseeable risk management strategies to prevent core damage are constrained by the availability of first line systems as well as support systems. The actual trend in the evaluation of risk management options can be performed in a number of ways. An example is the identification of back-up systems which could be used to perform the same safety functions. In this work we deal with the evaluation of the feasibility, for BWR's, to use the Control Rod Drive system to maintain an adequate reactor core long term cooling in some accident sequences. This preliminary evaluation is carried out as a part of the Internal Events Analysis for Laguna Verde Nuclear Power Plant (LVNPP) that is currently under way by the Mexican Nuclear Regulatory Body. This analysis addresses the evaluation and incorporation of all the systems, including the safety related and the back-up non safety related systems, that are available for the operator in order to prevent core damage. As a part of this analysis the containment venting capability is also evaluated as a back-up of the containment heat removal function. This will prevent the primary containment overpressurization and loss of certain core cooling systems. A selection of accident sequences in which the Control Rod Drive system could be used to mitigate the accident and prevent core damage are discussed. A personal computer transient analysis code is used to carry out thermohydraulic simulations in order to evaluate the Control Rod Drive system performance, the corresponding results are presented. Finally, some preliminary conclusions are drawn. (author). 9 refs, 5 figs

  7. Dynamic event Tress applied to sequences Full Spectrum LOCA. Calculating the frequency of exceedance of damage by integrated Safety Analysis Methodology; Arboles de sucesos dinamicos aplicados a secuencias Full Spectrum LOCA. Calculo de la frequencia de excedencia del dano mediante la metodologia Analisis Integrados de Seguridad (ISA)

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Magan, J. J.; Fernandez, I.; Gil, J.; Marrao, H.; Queral, C.; Gonzalez-Cadelo, J.; Montero-Mayorga, J.; Rivas, J.; Ibane-Llano, C.; Izquierdo, J. M.; Sanchez-Perea, M.; Melendez, E.; Hortal, J.

    2013-09-01

    The Integrated Safety Analysis (ISA) methodology, developed by the Spanish Nuclear Safety council (CSN), has been applied to obtain the dynamic Event Trees (DETs) for full spectrum Loss of Coolant Accidents (LOCAs) of a Westinghouse 3-loop PWR plant. The purpose of this ISA application is to obtain the Damage Exceedance Frequency (DEF) for the LOCA Event Tree by taking into account the uncertainties in the break area and the operator actuation time needed to cool down and de pressurize reactor coolant system by means of steam generator. Simulations are performed with SCAIS, a software tool which includes a dynamic coupling with MAAP thermal hydraulic code. The results show the capability of the ISA methodology to obtain the DEF taking into account the time uncertainty in human actions. (Author)

  8. Optimized core loading sequence for Ukraine WWER-1000 reactors

    International Nuclear Information System (INIS)

    Dye, M.; Shah, H.

    2015-01-01

    Fuel Assemblies (WFAs) experienced mechanical damage of the grids during loading at both South Ukraine 2 (SU2) and South Ukraine 3 (SU3). The grids were damaged due to high lateral loads exceeding their strength limit. The high lateral loads were caused by a combination of distortion and stiffness of the mixed core fuel assemblies and significant fuel assembly-to-fuel assembly interaction combined with the core loading sequence being used. To prevent damage of the WFA grids during core loading, Westinghouse has developed a loading sequence technique and loading aides (smooth sided dummies and top nozzle loading guides) designed to minimize fuel assembly-to-fuel assembly interaction while maximizing the potential for successful loading (i.e., no fuel assembly damage and minimized loading time). The loading sequence technique accounts for cycle-specific core loading patterns and is based on previous Westinghouse WWER core loading experience and fundamental principles. The loading aids are developed to “open-up” the target core location or to provide guidance into a target core location. The Westinghouse optimized core loading sequence and smooth sided dummies were utilized during the successful loading of SU3 Cycle 25 mixed core in March 2015, with no instances of fuel assembly damage and yet still provided considerable time savings relative to the 2012 and 2013 SU3 reload campaigns. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  10. Side core lifter

    Energy Technology Data Exchange (ETDEWEB)

    Edelman, Ya A

    1982-01-01

    A side core lifter is proposed which contains a housing with guide slits and a removable core lifter with side projections on the support section connected to the core receiver. In order to preserve the structure of the rock in the core sample by means of guaranteeing rectilinear movement of the core lifter in the rock, the support and core receiver sections are hinged. The device is equipped with a spring for angular shift in the core-reception part.

  11. Flood damage curves for consistent global risk assessments

    Science.gov (United States)

    de Moel, Hans; Huizinga, Jan; Szewczyk, Wojtek

    2016-04-01

    Assessing potential damage of flood events is an important component in flood risk management. Determining direct flood damage is commonly done using depth-damage curves, which denote the flood damage that would occur at specific water depths per asset or land-use class. Many countries around the world have developed flood damage models using such curves which are based on analysis of past flood events and/or on expert judgement. However, such damage curves are not available for all regions, which hampers damage assessments in those regions. Moreover, due to different methodologies employed for various damage models in different countries, damage assessments cannot be directly compared with each other, obstructing also supra-national flood damage assessments. To address these problems, a globally consistent dataset of depth-damage curves has been developed. This dataset contains damage curves depicting percent of damage as a function of water depth as well as maximum damage values for a variety of assets and land use classes (i.e. residential, commercial, agriculture). Based on an extensive literature survey concave damage curves have been developed for each continent, while differentiation in flood damage between countries is established by determining maximum damage values at the country scale. These maximum damage values are based on construction cost surveys from multinational construction companies, which provide a coherent set of detailed building cost data across dozens of countries. A consistent set of maximum flood damage values for all countries was computed using statistical regressions with socio-economic World Development Indicators from the World Bank. Further, based on insights from the literature survey, guidance is also given on how the damage curves and maximum damage values can be adjusted for specific local circumstances, such as urban vs. rural locations, use of specific building material, etc. This dataset can be used for consistent supra

  12. Core cooling system for reactor

    International Nuclear Information System (INIS)

    Kondo, Ryoichi; Amada, Tatsuo.

    1976-01-01

    Purpose: To improve the function of residual heat dissipation from the reactor core in case of emergency by providing a secondary cooling system flow channel, through which fluid having been subjected to heat exchange with the fluid flowing in a primary cooling system flow channel flows, with a core residual heat removal system in parallel with a main cooling system provided with a steam generator. Constitution: Heat generated in the core during normal reactor operation is transferred from a primary cooling system flow channel to a secondary cooling system flow channel through a main heat exchanger and then transferred through a steam generator to a water-steam system flow channel. In the event if removal of heat from the core by the main cooling system becomes impossible due to such cause as breakage of the duct line of the primary cooling system flow channel or a trouble in a primary cooling system pump, a flow control valve is opened, and steam generator inlet and outlet valves are closed, thus increasing the flow rate in the core residual heat removal system. Thereafter, a blower is started to cause dissipation of the core residual heat from the flow channel of a system for heat dissipation to atmosphere. (Seki, T.)

  13. Reference accident (Core disruption accident - safety analysis detailed report no. 11)

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-15

    The PEC safety analysis led to the conclusion that all credible sequences (incident sequences characterized by a frequency of occurrence above 10/sup minus 7/ events per year) are limited to the design basis conditions of components of the plant protection systems, and that none of them leads to a release of mechanical energy or to an extensive damage of the core and primary containment structures event in the case of failure to scram. Nevertheless, as is done in other countries for similar reactors, some events beyond the limits of credibility were considered for the PEC reactor. These were defined on a absolutely hypothetical basis that involves severe core disruption and dynamic loading of primary containment boundary. A series of containments, each having a different role, was designed to mitigate the radiological effects of a postulated core disruptive accident. The final aim was to demonstrate that residual heat can be removed and that the release of radioactivity to the environment is within acceptable limits.

  14. A core performance study on an actinide recycling 'zero-sodium-void worth' core

    International Nuclear Information System (INIS)

    Kawashima, M.; Nakagawa, M.; Yamaoka, M.; Kasahara, F.

    1994-01-01

    A core performance study was made for an absorber-type parfait core (A-APC) as one of 'Zero-sodium-void-worth' core concepts. This evaluation study pursued different two aspects; one for transuranic (TRU) management strategy, and another for a loss-of-coolant anticipated transient behavior considering the unique core configuration. The results indicated that this core has a large flexibility for actinide recycling in terms of self-sufficiency and minor actinide burning. The result also showed that this core has kept a large mitigation potential for ULOF events as well as a simple flat core concept, reflecting detailed three dimensional core bowing behavior for the A-APC configuration. (author)

  15. Multi-scale fracture damage associated with underground chemical explosions

    Science.gov (United States)

    Swanson, E. M.; Sussman, A. J.; Wilson, J. E.; Townsend, M. J.; Prothro, L. B.; Gang, H. E.

    2018-05-01

    Understanding rock damage induced by explosions is critical for a number of applications including the monitoring and verification of underground nuclear explosions, mine safety issues, and modeling fluid flow through fractured rock. We use core observations, televiewer logs, and thin section observations to investigate fracture damage associated with two successive underground chemical explosions (SPE2 and SPE3) in granitic rock at both the mesoscale and microscale. We compare the frequency and orientations of core-scale fractures, and the frequency of microfractures, between a pre-experiment core and three post-experiment cores. Natural fault zones and explosion-induced fractures in the vicinity of the explosive source are readily apparent in recovered core and in thin sections. Damage from faults and explosions is not always apparent in fracture frequency plots from televiewer logs, although orientation data from these logs suggests explosion-induced fracturing may not align with the pre-existing fracture sets. Core-scale observations indicate the extent of explosion-induced damage is 10.0 m after SPE2 and 6.8 m after SPE3, despite both a similar size and location for both explosions. At the microscale, damage is observed to a range distance of 10.2 ± 0.9 m after SPE2, and 16.6 ± 0.9 and 11.2 ± 0.6 in two different cores collected after SPE3. Additional explosion-induced damage, interpreted to be the result of spalling, is readily apparent near the surface, but only in the microfracture data. This depth extent and intensity of damage in the near-surface region also increased after an additional explosion. This study highlights the importance of evaluating structural damage at multiple scales for a more complete characterization of the damage, and particularly shows the importance of microscale observations for identifying spallation-induced damage.

  16. External flooding event analysis in a PWR-W with MAAP5

    International Nuclear Information System (INIS)

    Fernandez-Cosials, Mikel Kevin; Jimenez, Gonzalo; Barreira, Pilar; Queral, Cesar

    2015-01-01

    Highlights: • External flooding preceded by a SCRAM is simulated with MAAP5.01. • Sensitivities include AFW-TDP, SLOCA and operator preventive actions. • SLOCA flow is the dominant factor in the sequences. • Vessel failure is avoidable with operator preventive actions. - Abstract: The Fukushima accident has drawn attention even more to the importance of external events and loss of energy supply on safety analysis. Since 2011, several Station Blackout (SBO) analyses have been done for all type of reactors. The most post-Fukushima studies analyze a pure and straight SBO transient, but the Fukushima accident was more complex than a standard SBO. At Fukushima accident, the SBO was a consequence of an external flooding from the tsunami and occurred 40 min after an emergency shutdown (SCRAM) caused by the earthquake. The first objective of this paper is to assume the consequences of an external flooding accident in a PWR site caused by a river flood, a dam break or a tsunami, where all the plant is damaged, not only the diesel generators. The second objective is to analyze possible actions to be performed in the time between the earthquake event (that causes a SCRAM) and the external flooding arrival, which could be applicable to accidents such as dam failures or river flooding in order to avoid more severe consequences, delay the core damage and improve the accident management. The results reveal how the actuation of the different systems and equipments affect the core damage time and how some actions could delay the core damage time enough to increase the possibility of AC power recovery

  17. Report on Fukushima Daiichi NPP precursor events

    International Nuclear Information System (INIS)

    2014-01-01

    The main questions to be answered by this report were: The Fukushima Daiichi NPP accident, could it have been prevented? If there is a next severe accident, may it be prevented? To answer the first question, the report addressed several aspects. First, the report investigated whether precursors to the Fukushima Daiichi NPP accident existed in the operating experience; second, the reasons why these precursors did not evolve into a severe accident. Third, whether lessons learned from these precursor events were adequately considered by member countries; and finally, if the operating experience feedback system needs to be improved, based on the previous analysis. To address the second question which is much more challenging, the report considered precursor events identified through a search and analysis of the IRS database and also precursors events based on risk significance. Both methods can point out areas where further work may be needed, even if it depends heavily on design and site-specific factors. From the operating experience side, more efforts are needed to ensure timely and full implementation of lessons learnt from precursor events. Concerning risk considerations, a combined use of risk precursors and operating experience may drive to effective changes to plants to reduce risk. The report also contains a short description and evaluation of selected precursors that are related to the course of the Fukushima Daiichi NPP accident. The report addresses the question whether operating experience feedback can be effectively used to identify plant vulnerabilities and minimize potential for severe core damage accidents. Based on several of the precursor events national or international in-depth evaluations were started. The vulnerability of NPPs due to external and internal flooding has clearly been addressed. In addition to the IRS based investigation, the WGRISK was asked to identify important precursor events based on risk significance. These precursors have

  18. Animal MRI Core

    Data.gov (United States)

    Federal Laboratory Consortium — The Animal Magnetic Resonance Imaging (MRI) Core develops and optimizes MRI methods for cardiovascular imaging of mice and rats. The Core provides imaging expertise,...

  19. Analysis of internal events for the Unit 1 of the Laguna Verde Nuclear Power Station. Appendixes

    International Nuclear Information System (INIS)

    Huerta B, A.; Lopez M, R.

    1995-01-01

    This volume contains the appendices for the accident sequences analysis for those internally initiated events for Laguna Verde Unit 1, Nuclear Power Plant. The appendix A presents the comments raised by the Sandia National Laboratories technical staff as a result of the review of the Internal Event Analysis for Laguna Verde Unit 1 Nuclear Power Plant. This review was performed during a joint Sandia/CNSNS multi-day meeting by the end 1992. Also included is a brief evaluation on the applicability of these comments to the present study. The appendix B presents the fault tree models printed for each of the systems included and.analyzed in the Internal Event Analysis for LVNPP. The appendice C presents the outputs of the TEMAC code, used for the cuantification of the dominant accident sequences as well as for the final core damage evaluation. (Author)

  20. Analysis of internal events for the Unit 1 of the Laguna Verde Nuclear Power Station. Appendixes

    International Nuclear Information System (INIS)

    Huerta B, A.; Lopez M, R.

    1995-01-01

    This volume contains the appendices for the accident sequences analysis for those internally initiated events for Laguna Verde Unit 1, Nuclear Power Plant. The appendix A presents the comments raised by the Sandia National Laboratories technical staff as a result of the review of the Internal Event Analysis for Laguna Verde Unit 1 Nuclear Power Plant. This review was performed during a joint Sandia/CNSNS multi-day meeting by the end 1992. Also included is a brief evaluation on the applicability of these comments to the present study. The appendix B presents the fault tree models printed for each of the systems included and analyzed in the Internal Event Analysis for LVNPP. The appendice C presents the outputs of the TEMAC code, used for the cuantification of the dominant accident sequences as well as for the final core damage evaluation. (Author)

  1. ROSA full-core and DNBR capabilities

    International Nuclear Information System (INIS)

    Gibcus, H.P.M.; Verhagen, F.C.M.; Wakker, P.H.

    2013-01-01

    The latest developments of the ROSA (Reloading Optimization by Simulated Annealing) code system with an emphasis on the first full-core version and the minimum DNBR (Departure from Nucleate Boiling Ratio) as a new optimization parameter are presented. Designing the core loading pattern of nuclear power plants is becoming a more and more complex task. This task becomes even more complicated if asymmetries in the core loading pattern arise, for instance due to damaged fuel assemblies. For over almost 2 decades ROSA, NRG's (Nuclear Research and consultancy Group) loading pattern optimization code system for PWRs, has proven to be a valuable tool to reactor operators in accomplishing this task. To improve the use of ROSA for designing asymmetric loading patterns, NRG has developed a full-core version of ROSA besides the original quarter-core version which requires rotational symmetry in the computational domain. The extension of ROSA with DNBR as an optimization parameter is part of ROSA's continuous development. (orig.)

  2. Procedure for conducting probabilistic safety assessment: level 1 full power internal event analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Won Dae; Lee, Y. H.; Hwang, M. J. [and others

    2003-07-01

    This report provides guidance on conducting a Level I PSA for internal events in NPPs, which is based on the method and procedure that was used in the PSA for the design of Korea Standard Nuclear Plants (KSNPs). Level I PSA is to delineate the accident sequences leading to core damage and to estimate their frequencies. It has been directly used for assessing and modifying the system safety and reliability as a key and base part of PSA. Also, Level I PSA provides insights into design weakness and into ways of preventing core damage, which in most cases is the precursor to accidents leading to major accidents. So Level I PSA has been used as the essential technical bases for risk-informed application in NPPs. The report consists six major procedural steps for Level I PSA; familiarization of plant, initiating event analysis, event tree analysis, system fault tree analysis, reliability data analysis, and accident sequence quantification. The report is intended to assist technical persons performing Level I PSA for NPPs. A particular aim is to promote a standardized framework, terminology and form of documentation for PSAs. On the other hand, this report would be useful for the managers or regulatory persons related to risk-informed regulation, and also for conducting PSA for other industries.

  3. Ex-vessel molten core debris interactions at CANDU nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, M J; Oyinloye, J O; Chambers, I [Electrowatt Consulting Engineers and Scientists, Warrington, Cheshire (United Kingdom); Scott, C K [Atlantic Nuclear Services, Fredericton, NB (Canada); Omar, A M [Atomic Energy Control Board, Ottawa, ON (Canada)

    1991-12-31

    Currently, the Atomic Energy Control Board (AECB) of Canada is sponsoring a project with a long term objective of obtaining an evaluation, independent of the industry, of the consequences to the public and the environment of postulated severe accidents at a Canadian nuclear power plant. Phase 1 of this project is a scoping study conducted to establish the relative consequences of a number of postulated event sequences. The studies in this paper model a multi-unit CANDU reactor at which pre-defined initiating events and their consequences could lead to severe core damage and relocation of the core debris onto the floor of the concrete reactor vault. Depending on the accident sequence assumptions made, an overlying pool of water may or may not be present. The US-NRC computer code CORCON Mod 2.0 was used to calculate the behaviour of the core material interacting with the concrete. The code calculates the decomposition of concrete by the molten core, and also the gases produced, which are released into the containment. The challenges to containment integrity are described, from the viewpoint of foundation decomposition and failure due to overpressure. The containment thermal-hydraulic behaviour is examined using an in-house computer code (CREM) written for this purpose. It is found that the containment envelope, in the absence of mitigating operator actions or design safety features, even for a case involving early core disassembly with the vacuum building unavailable, is unlikely to be failed within the 48 hours time frame examined. The paper identifies several areas for improvement in the models for future studies of core-concrete interactions for CANDU reactor plants. (author). 8 refs., 1 tab., 5 figs.

  4. Ex-vessel molten core debris interactions at CANDU nuclear power plants

    International Nuclear Information System (INIS)

    Lewis, M.J.; Oyinloye, J.O.; Chambers, I.; Scott, C.K.; Omar, A.M.

    1990-01-01

    Currently, the Atomic Energy Control Board (AECB) of Canada is sponsoring a project with a long term objective of obtaining an evaluation, independent of the industry, of the consequences to the public and the environment of postulated severe accidents at a Canadian nuclear power plant. Phase 1 of this project is a scoping study conducted to establish the relative consequences of a number of postulated event sequences. The studies in this paper model a multi-unit CANDU reactor at which pre-defined initiating events and their consequences could lead to severe core damage and relocation of the core debris onto the floor of the concrete reactor vault. Depending on the accident sequence assumptions made, an overlying pool of water may or may not be present. The US-NRC computer code CORCON Mod 2.0 was used to calculate the behaviour of the core material interacting with the concrete. The code calculates the decomposition of concrete by the molten core, and also the gases produced, which are released into the containment. The challenges to containment integrity are described, from the viewpoint of foundation decomposition and failure due to overpressure. The containment thermal-hydraulic behaviour is examined using an in-house computer code (CREM) written for this purpose. It is found that the containment envelope, in the absence of mitigating operator actions or design safety features, even for a case involving early core disassembly with the vacuum building unavailable, is unlikely to be failed within the 48 hours time frame examined. The paper identifies several areas for improvement in the models for future studies of core-concrete interactions for CANDU reactor plants. (author). 8 refs., 1 tab., 5 figs

  5. Automated Damage Onset Analysis Techniques Applied to KDP Damage and the Zeus Small Area Damage Test Facility

    International Nuclear Information System (INIS)

    Sharp, R.; Runkel, M.

    1999-01-01

    Automated damage testing of KDP using LLNL's Zeus automated damage test system has allowed the statistics of KDP bulk damage to be investigated. Samples are now characterized by the cumulative damage probability curve, or S-curve, that is generated from hundreds of individual test sites per sample. A HeNe laser/PMT scatter diagnostic is used to determine the onset of damage at each test site. The nature of KDP bulk damage is such that each scatter signal may possess many different indicators of a damage event. Because of this, the determination of the initial onset for each scatter trace is not a straightforward affair and has required considerable manual analysis. The amount of testing required by crystal development for the National Ignition Facility (NIF) has made it impractical to continue analysis by hand. Because of this, we have developed and implemented algorithms for analyzing the scatter traces by computer. We discuss the signal cleaning algorithms and damage determination criteria that have lead to the successful implementation of a LabView based analysis code. For the typical R/1 damage data set, the program can find the correct damage onset in more than 80% of the cases, with the remaining 20% being left to operator determination. The potential time savings for data analysis is on the order of ∼ 100X over manual analysis and is expected to result in the savings of at least 400 man-hours over the next 3 years of NIF quality assurance testing

  6. Fusion events

    International Nuclear Information System (INIS)

    Aboufirassi, M; Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Meslin, C.; Metivier, V.; Nakagawa, T.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Wieloch, A.; Yuasa-Nakagawa, K.

    1998-01-01

    The fusion reactions between low energy heavy ions have a very high cross section. First measurements at energies around 30-40 MeV/nucleon indicated no residue of either complete or incomplete fusion, thus demonstrating the disappearance of this process. This is explained as being due to the high amount o energies transferred to the nucleus, what leads to its total dislocation in light fragments and particles. Exclusive analyses have permitted to mark clearly the presence of fusion processes in heavy systems at energies above 30-40 MeV/nucleon. Among the complete events of the Kr + Au reaction at 60 MeV/nucleon the majority correspond to binary collisions. Nevertheless, for the most considerable energy losses, a class of events do occur for which the detected fragments appears to be emitted from a unique source. These events correspond to an incomplete projectile-target fusion followed by a multifragmentation. Such events were singled out also in the reaction Xe + Sn at 50 MeV/nucleon. For the events in which the energy dissipation was maximal it was possible to isolate an isotropic group of events showing all the characteristics of fusion nuclei. The fusion is said to be incomplete as pre-equilibrium Z = 1 and Z = 2 particles are emitted. The cross section is of the order of 25 mb. Similar conclusions were drown for the systems 36 Ar + 27 Al and 64 Zn + nat Ti. A cross section value of ∼ 20 mb was determined at 55 MeV/nucleon in the first case, while the measurement of evaporation light residues in the last system gave an upper limit of 20-30 mb for the cross section at 50 MeV/nucleon

  7. PBF severe fuel damage program: results and comparison to analysis

    International Nuclear Information System (INIS)

    McDonald, P.E.; Buescher, B.J.; Gruen, G.E.; Hobbins, R.R.; McCardell, R.K.

    1983-01-01

    The United States Nuclear Regulatory Commission has initiated a severe fuel damage research program in the Power Burst Facility (PBF) to investigate fuel rod and core response, and fission product and hydrogen release and transport under degraded core cooling accident conditions. This paper presents a description of Phase I of the PBF Severe Fuel Damage Program, discusses the results of the first experiment, and compares those results with analysis performed using the TRAC-BD1 computer code

  8. DNA Damage, Mutagenesis and Cancer

    Directory of Open Access Journals (Sweden)

    Ashis K. Basu

    2018-03-01

    Full Text Available A large number of chemicals and several physical agents, such as UV light and γ-radiation, have been associated with the etiology of human cancer. Generation of DNA damage (also known as DNA adducts or lesions induced by these agents is an important first step in the process of carcinogenesis. Evolutionary processes gave rise to DNA repair tools that are efficient in repairing damaged DNA; yet replication of damaged DNA may take place prior to repair, particularly when they are induced at a high frequency. Damaged DNA replication may lead to gene mutations, which in turn may give rise to altered proteins. Mutations in an oncogene, a tumor-suppressor gene, or a gene that controls the cell cycle can generate a clonal cell population with a distinct advantage in proliferation. Many such events, broadly divided into the stages of initiation, promotion, and progression, which may occur over a long period of time and transpire in the context of chronic exposure to carcinogens, can lead to the induction of human cancer. This is exemplified in the long-term use of tobacco being responsible for an increased risk of lung cancer. This mini-review attempts to summarize this wide area that centers on DNA damage as it relates to the development of human cancer.

  9. Temporal Change of Seismic Earth's Inner Core Phases: Inner Core Differential Rotation Or Temporal Change of Inner Core Surface?

    Science.gov (United States)

    Yao, J.; Tian, D.; Sun, L.; Wen, L.

    2017-12-01

    Since Song and Richards [1996] first reported seismic evidence for temporal change of PKIKP wave (a compressional wave refracted in the inner core) and proposed inner core differential rotation as its explanation, it has generated enormous interests in the scientific community and the public, and has motivated many studies on the implications of the inner core differential rotation. However, since Wen [2006] reported seismic evidence for temporal change of PKiKP wave (a compressional wave reflected from the inner core boundary) that requires temporal change of inner core surface, both interpretations for the temporal change of inner core phases have existed, i.e., inner core rotation and temporal change of inner core surface. In this study, we discuss the issue of the interpretation of the observed temporal changes of those inner core phases and conclude that inner core differential rotation is not only not required but also in contradiction with three lines of seismic evidence from global repeating earthquakes. Firstly, inner core differential rotation provides an implausible explanation for a disappearing inner core scatterer between a doublet in South Sandwich Islands (SSI), which is located to be beneath northern Brazil based on PKIKP and PKiKP coda waves of the earlier event of the doublet. Secondly, temporal change of PKIKP and its coda waves among a cluster in SSI is inconsistent with the interpretation of inner core differential rotation, with one set of the data requiring inner core rotation and the other requiring non-rotation. Thirdly, it's not reasonable to invoke inner core differential rotation to explain travel time change of PKiKP waves in a very small time scale (several months), which is observed for repeating earthquakes in Middle America subduction zone. On the other hand, temporal change of inner core surface could provide a consistent explanation for all the observed temporal changes of PKIKP and PKiKP and their coda waves. We conclude that

  10. Degraded core studies at INEL

    International Nuclear Information System (INIS)

    Buescher, B.J.; Howe, T.M.; Miller, R.W.

    1982-01-01

    During 1980, planning of prototypical severe fuel damage tests to be conducted in the Power Burst Facility (PBF) to investigate fuel behavior in severe accidents up to temperatures of 2400 0 K was initiated. This first series of tests is designated Phase I. Also, a code development effort was initiated to provide a reliable predictive tool for core behavior during severe accidents. During 1981, an assessment of capabilities and preliminary planning were begun for an in-pile experimental program to investigate the behavior of larger arrays of previously irradiated fuel rods at temperatures through UO 2 melting. This latter series of tests is designated Phase II

  11. TMI-2 Core Shipping Preparations

    International Nuclear Information System (INIS)

    Ball, L.J.; Barkanic, R.J.; Conaway, W.T. II; Schmoker, D. S.; Post, Roy G.

    1988-01-01

    Shipping the damaged core from the Unit 2 reactor of Three Mile Island Nuclear Power Station near Harrisburg, PA, to the Idaho National Engineering Laboratory near Idaho Falls, ID, required development and implementation of a completely new spent fuel transportation system. This paper describes of the equipment developed, the planning and activities used to implement the hard-ware-systems into the facilities, and the planning involved in making the rail shipments. It also includes a summary of recommendations resulting from this experience. (author)

  12. Damage analysis: damage function development and application

    International Nuclear Information System (INIS)

    Simons, R.L.; Odette, G.R.

    1975-01-01

    The derivation and application of damage functions, including recent developments for the U.S. LMFBR and CTR programs, is reviewed. A primary application of damage functions is in predicting component life expectancies; i.e., the fluence required in a service spectrum to attain a specified design property change. An important part of the analysis is the estimation of the uncertainty in such fluence limit predictions. The status of standardizing the procedures for the derivation and application of damage functions is discussed. Improvements in several areas of damage function development are needed before standardization can be completed. These include increasing the quantity and quality of the data used in the analysis, determining the limitations of the analysis due to the presence of multiple damage mechanisms, and finally, testing of damage function predictions against data obtained from material surveillance programs in operating thermal and fast reactors. 23 references. (auth)

  13. A core design study for 'zero-sodium-void-worth' cores

    International Nuclear Information System (INIS)

    Kawashima, Masatoshi; Suzuki, Masao; Hill, R.N.

    1992-01-01

    Recently, a number of low sodium-void-worth metal-fueled core design concepts have been proposed; to provide for flexibility in transuranic nuclide management strategy, core designs which exhibit a wide range of breeding characteristics have been developed. Two core concepts, a flat annular (transuranic burning) core and an absorber-type parfait (transuranic self-sufficient) core, are selected for this study. In this paper, the excess reactivity management schemes applied in the two designs are investigated in detail. In addition, the transient effect of reactivity insertions on the parfait core design is assessed. The upper and lower core regions in the parfait design are neutronically decoupled; however, the common coolant channel creates thermalhydraulic coupling. This combination of neutronic and thermalhydraulic characteristics leads to unique behavior in anticipated transient overpower events. (author)

  14. Iodine behaviour in PWR accidents leading to severe core damage

    International Nuclear Information System (INIS)

    Lucas, M.; Devillers, C.; Fermandjian, J.; Manesse, D.

    1982-09-01

    This paper deals with the iodine partition coefficient between the water at the bottom of the reactor building and the atmosphere above it. Molecular iodine is considered as a potential contributor to the airborne activity inside the reactor building. The concentration of molecular iodine in the containment atmosphere will depend, on one hand, upon mechanisms which generate that species and, on the other hand, upon the kinetics of chemical reactions which consume that species. Experiments have therefore been performed on the two following items: - molecular iodine formation through ν radiation from cesium iodide aerosols (droplets) in the reactor containment building, for doses ranging between 1.2 and 8 MRad (12 and 80 kSv), with solutions of various pH's and at different temperatures, - rate of hypoiodous acid disproportionation into iodate and iodide influencing further behavior of molecular iodine

  15. Modeling of reflood of severely damaged reactor core

    OpenAIRE

    Bachrata, Andrea

    2012-01-01

    Les événements récents au Japon sur les centrales nucléaires de Fukushima ont montré que des accidents conduisant à la fusion du cœur peuvent survenir bine plus souvent qu’on ne l’avait supposé et que leur impact sur l’environnement et la vie publique est considérable. Pour les réacteurs actuels, un des moyens principaux pour stopper la progression de l’accident est de tenter de refroidir le plus rapidement possible les matériaux en utiliser une injection d’eau de secours. Suivant l’instant d...

  16. Summary of core damage frequency from internal initiators: Peach Bottom

    International Nuclear Information System (INIS)

    Kolaczkowski, A.M.; Lambright, J.A.; Cathey, N.

    1986-01-01

    Probabilistic risk assessments (PRA) based on internal initiators are being conducted on a number of reference plants in order to provide the Nuclear Regulatory Commission (NRC) with updated information about light water reactor risk. The results of these analyses will be used by the NRC to prepare NUREG-1150 which will examine the NRC's current perception of risk. Peach Bottom has been chosen as one of the reference plants

  17. Development of Pipeline Database and CAD Model for Selection of Core Security Zone in Nuclear Power Plants

    International Nuclear Information System (INIS)

    Choi, Seong Soo; Kwon, Tae Gyun; Baek, Hun Hyun; Kwon, Min Jin

    2008-07-01

    The objective of the project is to develop the pipeline database which can be used for selection of core security zones considering safety significance of pipes and to develop CAD model for 3-dimensional visualization of core security zones, for the purpose of minimizing damage and loss, enforcing security and protection on important facilities, and improving plant design preparing against emergency situations such as physical terrors in nuclear power plants. In this study, the pipeline database is developed for selection of core security zones considering safety significance of safety class 1 and 2 pipes. The database includes the information on 'pipe-room information-surrogate component' mapping, initiating events which may occur and accident mitigation functions which may be damaged by the pipe failure, and the drawing information related to 2,270 pipe segments of 30 systems. For the 3-dimensional visualization of core security zones, the CAD models on the containment building and the auxiliary building are developed using 3-D MAX tool and the demo program which can visualize the direct-X model converted from the 3-D MAX model is also developed. In addition to this, the coordinate information of all the buildings and their rooms is generated using AUTO CAD tool in order to be used as an input for 3-dimensional browsing of the VIP program

  18. Core Hunter 3: flexible core subset selection.

    Science.gov (United States)

    De Beukelaer, Herman; Davenport, Guy F; Fack, Veerle

    2018-05-31

    Core collections provide genebank curators and plant breeders a way to reduce size of their collections and populations, while minimizing impact on genetic diversity and allele frequency. Many methods have been proposed to generate core collections, often using distance metrics to quantify the similarity of two accessions, based on genetic marker data or phenotypic traits. Core Hunter is a multi-purpose core subset selection tool that uses local search algorithms to generate subsets relying on one or more metrics, including several distance metrics and allelic richness. In version 3 of Core Hunter (CH3) we have incorporated two new, improved methods for summarizing distances to quantify diversity or representativeness of the core collection. A comparison of CH3 and Core Hunter 2 (CH2) showed that these new metrics can be effectively optimized with less complex algorithms, as compared to those used in CH2. CH3 is more effective at maximizing the improved diversity metric than CH2, still ensures a high average and minimum distance, and is faster for large datasets. Using CH3, a simple stochastic hill-climber is able to find highly diverse core collections, and the more advanced parallel tempering algorithm further increases the quality of the core and further reduces variability across independent samples. We also evaluate the ability of CH3 to simultaneously maximize diversity, and either representativeness or allelic richness, and compare the results with those of the GDOpt and SimEli methods. CH3 can sample equally representative cores as GDOpt, which was specifically designed for this purpose, and is able to construct cores that are simultaneously more diverse, and either are more representative or have higher allelic richness, than those obtained by SimEli. In version 3, Core Hunter has been updated to include two new core subset selection metrics that construct cores for representativeness or diversity, with improved performance. It combines and outperforms the

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-06-01

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

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

    International Nuclear Information System (INIS)

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

    1994-06-01

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

  1. k-core covers and the core

    NARCIS (Netherlands)

    Sanchez-Rodriguez, E.; Borm, Peter; Estevez-Fernandez, A.; Fiestras-Janeiro, G.; Mosquera, M.A.

    This paper extends the notion of individual minimal rights for a transferable utility game (TU-game) to coalitional minimal rights using minimal balanced families of a specific type, thus defining a corresponding minimal rights game. It is shown that the core of a TU-game coincides with the core of

  2. Radiation damage of nonmetallic solids

    International Nuclear Information System (INIS)

    Goland, A.N.

    1975-01-01

    A review of data and information on radiation damage in nonmetallic solids is presented. Discussions are included on defects in nonmetals, radiation damage processes in nonmetals, electronic damage processes, physical damage processes, atomic displacement, photochemical damage processes, and ion implantation

  3. Reconstructing patterns of temperature, phenology, and frost damage over 124 years: spring damage risk is increasing.

    Science.gov (United States)

    Augspurger, Carol K

    2013-01-01

    Climate change, with both warmer spring temperatures and greater temperature fluctuations, has altered phenologies, possibly leading to greater risk of spring frost damage to temperate deciduous woody plants. Phenological observations of 20 woody species from 1993 to 2012 in Trelease Woods, Champaign County, Illinois, USA, were used to identify years with frost damage to vegetative and reproductive phases. Local temperature records were used in combination with the phenological observations to determine what combinations of the two were associated with damage. Finally, a long-term temperature record (1889-1992) was evaluated to determine if the frequency of frost damage has risen in recent decades. Frost Frost damage occurred in five years in the interior and in three additional years at only the forest edge. The degree of damage varied with species, life stage, tissue (vegetative or reproductive), and phenological phase. Common features associated with the occurrence of damage to interior plants were (1) a period of unusual warm temperatures in March, followed by (2) a frost event in April with a minimum temperature frost damage increased significantly, from 0.03 during 1889-1979 to 0.21 during 1980-2012. When the criteria were "softened" to frost damage events more common.

  4. Modeled seasonality of glacial abrupt climate events

    NARCIS (Netherlands)

    Flueckiger, J.; Knutti, R.; White, J.W.C.; Renssen, H.

    2008-01-01

    Greenland ice cores, as well as many other paleo-archives from the northern hemisphere, recorded a series of 25 warm interstadial events, the so-called Dansgaard-Oeschger (D-O) events, during the last glacial period. We use the three-dimensional coupled global ocean-atmosphere-sea ice model

  5. DNA damage by Auger emitters

    International Nuclear Information System (INIS)

    Martin, R.F.; d'Cunha, Glenn; Gibbs, Richard; Murray, Vincent; Pardee, Marshall; Allen, B.J.

    1988-01-01

    125 I atoms can be introduced at specific locations along a defined DNA target molecule, either by site-directed incorporation of an 125 I-labelled deoxynucleotide or by binding of an 125 I-labelled sequence-selective DNA ligand. After allowing accumulation of 125 I decay-induced damage to the DNA, application of DNA sequencing techniques enables positions of strand breaks to be located relative to the site of decay, at a resolution corresponding to the distance between adjacent nucleotides [0.34 nm]. Thus, DNA provides a molecular framework to analyse the extent of damage following [averaged] individual decay events. Results can be compared with energy deposition data generated by computer-simulation methods developed by Charlton et al. The DNA sequencing technique also provides information about the chemical nature of the termini of the DNA chains produced following Auger decay-induced damage. In addition to reviewing the application of this approach to the analysis of 125 I decay induced DNA damage, some more recent results obtained by using 67 Ga are also presented. (author)

  6. Improving Flood Damage Assessment Models in Italy

    Science.gov (United States)

    Amadio, M.; Mysiak, J.; Carrera, L.; Koks, E.

    2015-12-01

    The use of Stage-Damage Curve (SDC) models is prevalent in ex-ante assessments of flood risk. To assess the potential damage of a flood event, SDCs describe a relation between water depth and the associated potential economic damage over land use. This relation is normally developed and calibrated through site-specific analysis based on ex-post damage observations. In some cases (e.g. Italy) SDCs are transferred from other countries, undermining the accuracy and reliability of simulation results. Against this background, we developed a refined SDC model for Northern Italy, underpinned by damage compensation records from a recent flood event. Our analysis considers both damage to physical assets and production losses from business interruptions. While the first is calculated based on land use information, production losses are measured through the spatial distribution of Gross Value Added (GVA). An additional component of the model assesses crop-specific agricultural losses as a function of flood seasonality. Our results show an overestimation of asset damage from non-calibrated SDC values up to a factor of 4.5 for tested land use categories. Furthermore, we estimate that production losses amount to around 6 per cent of the annual GVA. Also, maximum yield losses are less than a half of the amount predicted by the standard SDC methods.

  7. Apparatus for controlling molten core debris

    International Nuclear Information System (INIS)

    Golden, M.P.; Tilbrook, R.W.; Heylmun, N.F.

    1972-01-01

    Disclosed is an apparatus for containing, cooling, diluting, dispersing and maintaining subcritical the molten core debris assumed to melt through the bottom of a nuclear reactor pressure vessel in the unlikely event of a core meltdown. The apparatus is basically a sacrificial bed system which includes an inverted conical funnel, a core debris receptacle including a spherical dome, a spherically layered bed of primarily magnesia bricks, a cooling system of zig-zag piping in graphite blocks about and below the bed and a cylindrical liner surrounding the graphite blocks including a steel shell surrounded by firebrick. Tantalum absorber rods are used in the receptacle and bed. 9 claims, 22 figures

  8. R and D non-destructive damage monitoring and diagnosing system for civil infrastructures

    International Nuclear Information System (INIS)

    Ren Weixin; Abu Bakar Mohamad Diah; Cheng Hao

    1998-01-01

    Since civil infrastructures serve as the underpinnings of our highly industrialized society, and much of them are now decaying, it is the time to consider how to maintain these widely spread infrastructures in order to prevent potential catastrophic events. Changes in use and the need to maintain an ageing system require improvements in instrumentation for sensing and recording, data acquisition for diagnosing the possible damage, and algorithm for identifying and monitoring the changes in structural characteristics. Researching and developing a real-time, in-serve health detection and monitoring system has drawn a worldwide attention recently for various types of structures. The paper conceives an integrated non-destructive damage monitoring and diagnosing system for civil infrastructures. The system is a high technology and high-commercialised industrial integrated product involved in research and development. The research activities of the system cover three core parts: structural modelling, structural system identification and damage criterion establishment. The development activities of the system include experimental measurements, data acquisition and processing, instrumentation set-up, computer visualisation, and software development. The state-of -the art theories and practices are systematically merged and integrated in the development of the system, and the system will be verified through the real world application for civil infrastructures. Our research results on the damage criterion based on the changes in structural dynamic properties are also reported in the paper. (Author)

  9. Quantitative risk trends deriving from PSA-based event analyses. Analysis of results from U.S.NRC's accident sequence precursor program

    International Nuclear Information System (INIS)

    Watanabe, Norio

    2004-01-01

    The United States Nuclear Regulatory Commission (U.S.NRC) has been carrying out the Accident Sequence Precursor (ASP) Program to identify and categorize precursors to potential severe core damage accident sequences using the probabilistic safety assessment (PSA) technique. The ASP Program has identified a lot of risk significant events as precursors that occurred at U.S. nuclear power plants. Although the results from the ASP Program include valuable information that could be useful for obtaining and characterizing risk significant insights and for monitoring risk trends in nuclear power industry, there are only a few attempts to determine and develop the trends using the ASP results. The present study examines and discusses quantitative risk trends for the industry level, using two indicators, that is, the occurrence frequency of precursors and the annual core damage probability, deriving from the results of the ASP analysis. It is shown that the core damage risk at U.S. nuclear power plants has been lowered and the likelihood of risk significant events has been remarkably decreasing. As well, the present study demonstrates that two risk indicators used here can provide quantitative information useful for examining and monitoring the risk trends and/or risk characteristics in nuclear power industry. (author)

  10. Femoral nerve damage (image)

    Science.gov (United States)

    The femoral nerve is located in the leg and supplies the muscles that assist help straighten the leg. It supplies sensation ... leg. One risk of damage to the femoral nerve is pelvic fracture. Symptoms of femoral nerve damage ...

  11. Event Index - a LHCb Event Search System

    CERN Document Server

    INSPIRE-00392208; Kazeev, Nikita; Redkin, Artem

    2015-12-23

    LHC experiments generate up to $10^{12}$ events per year. This paper describes Event Index - an event search system. Event Index's primary function is quickly selecting subsets of events from a combination of conditions, such as the estimated decay channel or stripping lines output. Event Index is essentially Apache Lucene optimized for read-only indexes distributed over independent shards on independent nodes.

  12. Single event burnout sensitivity of embedded field effect transistors

    International Nuclear Information System (INIS)

    Koga, R.; Crain, S.H.; Crawford, K.B.; Yu, P.; Gordon, M.J.

    1999-01-01

    Observations of single event burnout (SEB) in embedded field effect transistors are reported. Both SEB and other single event effects are presented for several pulse width modulation and high frequency devices. The microscope has been employed to locate and to investigate the damaged areas. A model of the damage mechanism based on the results so obtained is described

  13. Single event burnout sensitivity of embedded field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Koga, R.; Crain, S.H.; Crawford, K.B.; Yu, P.; Gordon, M.J.

    1999-12-01

    Observations of single event burnout (SEB) in embedded field effect transistors are reported. Both SEB and other single event effects are presented for several pulse width modulation and high frequency devices. The microscope has been employed to locate and to investigate the damaged areas. A model of the damage mechanism based on the results so obtained is described.

  14. Necrosome core machinery: MLKL.

    Science.gov (United States)

    Zhang, Jing; Yang, Yu; He, Wenyan; Sun, Liming

    2016-06-01

    In the study of regulated cell death, the rapidly expanding field of regulated necrosis, in particular necroptosis, has been drawing much attention. The signaling of necroptosis represents a sophisticated form of a death pathway. Anti-caspase mechanisms (e.g., using inhibitors of caspases, or genetic ablation of caspase-8) switch cell fate from apoptosis to necroptosis. The initial extracellular death signals regulate RIP1 and RIP3 kinase activation. The RIP3-associated death complex assembly is necessary and sufficient to initiate necroptosis. MLKL was initially identified as an essential mediator of RIP1/RIP3 kinase-initiated necroptosis. Recent studies on the signal transduction using chemical tools and biomarkers support the idea that MLKL is able to make more functional sense for the core machinery of the necroptosis death complex, called the necrosome, to connect to the necroptosis execution. The experimental data available now have pointed that the activated MLKL forms membrane-disrupting pores causing membrane leakage, which extends the prototypical concept of morphological and biochemical events following necroptosis happening in vivo. The key role of MLKL in necroptosis signaling thus sheds light on the logic underlying this unique "membrane-explosive" cell death pathway. In this review, we provide the general concepts and strategies that underlie signal transduction of this form of cell death, and then focus specifically on the role of MLKL in necroptosis.

  15. Development of Emergency Operating Strategies for Beyond Design Basis External Event(BDBEE)s in Korean WH Nuclear Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Duk-Joo; Lee, Seung-Chan; Sung, Je-Joong; Ha, Sang-Jun [KHNP CRI, Daejeon (Korea, Republic of); Hong, Soon-Joon; Hwang, Su-Hyun; Lee, Byung-Chul; Park, Kang-Min [FNC Tech. Co., Yongin (Korea, Republic of)

    2015-10-15

    Westinghouse developed and connected emergency operating procedures into a set of FLEX Support Guidelines(FSGs). This paper explains that Korean WH(Westinghouse) type nuclear power plants develop emergency operating strategies for ELAP(extended loss of all AC power), which include guidelines to use permanent and portable equipment as necessary to prevent core damage until AC power is restored from a reliable alternate source of AC power. The Korean emergency operating response strategies were developed to cope with a ELAP such as Fukushima event. The strategies include guidelines to prevent fuel damage using the FLEX equipment. Operators should take actions to prepare FLEX equipment within license basis SBO coping time. The loss of all AC power has been analyzed to identify the behavior of major NSSS process variables using RELAP computer code. The accident analysis showed that the plant does not result in fuel damage in 72 hours after an ELAP if operators take actions to cool RCS with opening of SG ADV in 5 gpm seal leak case. In this scenario, because ELAP is in process and all power cannot be used, operator should operate the FLEX equipment in order to actuate active equipment using the EOP fo SBO response. This strategy will prevent entering SAMG because this actions result in core cooling and stay in core exit temperature less than 650 .deg. C. Korean emergency operating guidelines(EOGs) will be developed using this strategies for response to the BDBEE.

  16. Reactor core fuel management

    International Nuclear Information System (INIS)

    Silvennoinen, P.

    1976-01-01

    The subject is covered in chapters, entitled: concepts of reactor physics; neutron diffusion; core heat transfer; reactivity; reactor operation; variables of core management; computer code modules; alternative reactor concepts; methods of optimization; general system aspects. (U.K.)

  17. Nuclear reactor core catcher

    International Nuclear Information System (INIS)

    1977-01-01

    A nuclear reactor core catcher is described for containing debris resulting from an accident causing core meltdown and which incorporates a method of cooling the debris by the circulation of a liquid coolant. (U.K.)

  18. Seismic core shroud

    International Nuclear Information System (INIS)

    Puri, A.; Mullooly, J.F.

    1981-01-01

    A core shroud is provided, comprising: a coolant boundary, following the shape of the core boundary, for channeling the coolant through the fuel assemblies; a cylindrical band positioned inside the core barrel and surrounding the coolant boundary; and support members extending from the coolant boundary to the band, for transferring load from the coolant boundary to the band. The shroud may be assembled in parts using automated welding techniques, and it may be adjusted to fit the reactor core easily

  19. Damage correlation in theory and practice

    International Nuclear Information System (INIS)

    Doran, D.G.; Odette, G.R.; Simons, R.L.; Mansur, L.K.

    1977-01-01

    Common to all reactor development work is the problem of differences between the irradiation environments used for materials testing and those typical of service conditions. Efforts are being made to develop damage models that incorporate irradiation parameters such as type and energy of radiation, flux, and exposure. Models relating radiation damage production and microstructural evolution to changes in mechanical properties are primitive. Nevertheless, they suggest that the inability to account quantitatively for differences in test and service neutron spectra leads to overly conservative design of out-of-core components. Direct experimental corroboration is difficult because of the low neutron fluxes associated with the desired soft spectra. Further development of mechanistic models and new approaches to model testing are needed. Models of the growth stage of swelling, on the other hand, are relatively advanced. These models are discussed briefly as an example of how damage models can be used to help guide and analyze irradiation experiments. Accelerated damage studies using charged particles are expected to continue. Current empirical correlations of damage rates can be given a firmer theoretical basis as analysis of experiments and modeling of damage continue to improve. Damage correlation methodology practices in reactor design must necessarily follow different rules from that practiced in materials research and development. Nevertheless, decreasing the gap between them is a laudable objective with potentially significant economic impact

  20. Core Values | NREL

    Science.gov (United States)

    Core Values Core Values NREL's core values are rooted in a safe and supportive work environment guide our everyday actions and efforts: Safe and supportive work environment Respect for the rights physical and social environment Integrity Maintain the highest standard of ethics, honesty, and integrity

  1. Sidewall coring shell

    Energy Technology Data Exchange (ETDEWEB)

    Edelman, Ya A; Konstantinov, L P; Martyshin, A N

    1966-12-12

    A sidewall coring shell consists of a housing and a detachable core catcher. The core lifter is provided with projections, the ends of which are situated in another plane, along the longitudinal axis of the lifter. The chamber has corresponding projections.

  2. Simulating events

    Energy Technology Data Exchange (ETDEWEB)

    Ferretti, C; Bruzzone, L [Techint Italimpianti, Milan (Italy)

    2000-06-01

    The Petacalco Marine terminal on the Pacific coast in the harbour of Lazaro Carclenas (Michoacan) in Mexico, provides coal to the thermoelectric power plant at Pdte Plutarco Elias Calles in the port area. The plant is being converted from oil to burn coal to generate 2100 MW of power. The article describes the layout of the terminal and equipment employed in the unloading, coal stacking, coal handling areas and the receiving area at the power plant. The contractor Techint Italimpianti has developed a software system, MHATIS, for marine terminal management which is nearly complete. The discrete event simulator with its graphic interface provides a real-type decision support system for simulating changes to the terminal operations and evaluating impacts. The article describes how MHATIS is used. 7 figs.

  3. Event generators

    International Nuclear Information System (INIS)

    Durand, D.; Gulminelli, F.; Lopez, O.; Vient, E.

    1998-01-01

    The results concerning the heavy ion collision simulations at Fermi energies by means of phenomenological models obtained in the last two years ar presented. The event generators are essentially following the phase of elaboration of analysis methods of data obtained by INDRA or NAUTILUS 4 π multidetectors. To identify and correctly quantify a phenomenon or a physical quantity it is necessary to verify by simulation the feasibility and validity of the analysis and also to estimate the bias introduced by the experimental filter. Many studies have shown this, for instance: the determination of the collision reaction plan for flow studies, determination of kinematical characteristics of the quasi-projectiles, and the excitation energy measurement stored in the hot nuclei. To Eugene, the currently utilised generator, several improvements were added: introduction of space-time correlations between the different products emitted in the decay of excited nuclei by calculating the trajectories of the particles in the final phase of the reaction; taking into account in the decay cascade of the discrete levels of the lighter fragments; the possibility of the schematically description of the explosion of the nucleus by simultaneous emission of multi-fragments. Thus, by comparing the calculations with the data relative to heavy systems studied with the NAUTILUS assembly it was possible to extract the time scales in the nuclear fragmentation. The utilisation of these event generators was extended to the analysis of INDRA data concerning the determination of the vaporization threshold in the collisions Ar + Ni and also the research of the expansion effects in the collisions Xe + Sn at 50 MeV/u

  4. Flood damage estimation of companies: A comparison of Stage-Damage-Functions and Random Forests

    Science.gov (United States)

    Sieg, Tobias; Kreibich, Heidi; Vogel, Kristin; Merz, Bruno

    2017-04-01

    The development of appropriate flood damage models plays an important role not only for the damage assessment after an event but also to develop adaptation and risk mitigation strategies. So called Stage-Damage-Functions (SDFs) are often applied as a standard approach to estimate flood damage. These functions assign a certain damage to the water depth depending on the use or other characteristics of the exposed objects. Recent studies apply machine learning algorithms like Random Forests (RFs) to model flood damage. These algorithms usually consider more influencing variables and promise to depict a more detailed insight into the damage processes. In addition they provide an inherent validation scheme. Our study focuses on direct, tangible damage of single companies. The objective is to model and validate the flood damage suffered by single companies with SDFs and RFs. The data sets used are taken from two surveys conducted after the floods in the Elbe and Danube catchments in the years 2002 and 2013 in Germany. Damage to buildings (n = 430), equipment (n = 651) as well as goods and stock (n = 530) are taken into account. The model outputs are validated via a comparison with the actual flood damage acquired by the surveys and subsequently compared with each other. This study investigates the gain in model performance with the use of additional data and the advantages and disadvantages of the RFs compared to SDFs. RFs show an increase in model performance with an increasing amount of data records over a comparatively large range, while the model performance of the SDFs is already saturated for a small set of records. In addition, the RFs are able to identify damage influencing variables, which improves the understanding of damage processes. Hence, RFs can slightly improve flood damage predictions and provide additional insight into the underlying mechanisms compared to SDFs.

  5. Repair of radiation damage in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Setlow, R.B.

    1981-01-01

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis.

  6. Repair of radiation damage in mammalian cells

    International Nuclear Information System (INIS)

    Setlow, R.B.

    1981-01-01

    The responses, such as survival, mutation, and carcinogenesis, of mammalian cells and tissues to radiation are dependent not only on the magnitude of the damage to macromolecular structures - DNA, RNA, protein, and membranes - but on the rates of macromolecular syntheses of cells relative to the half-lives of the damages. Cells possess a number of mechanisms for repairing damage to DNA. If the repair systems are rapid and error free, cells can tolerate much larger doses than if repair is slow or error prone. It is important to understand the effects of radiation and the repair of radiation damage because there exist reasonable amounts of epidemiological data that permits the construction of dose-response curves for humans. The shapes of such curves or the magnitude of the response will depend on repair. Radiation damage is emphasized because: (a) radiation dosimetry, with all its uncertainties for populations, is excellent compared to chemical dosimetry; (b) a number of cancer-prone diseases are known in which there are defects in DNA repair and radiation results in more chromosomal damage in cells from such individuals than in cells from normal individuals; (c) in some cases, specific radiation products in DNA have been correlated with biological effects, and (d) many chemical effects seem to mimic radiation effects. A further reason for emphasizing damage to DNA is the wealth of experimental evidence indicating that damages to DNA can be initiating events in carcinogenesis

  7. Rotary core drills

    Energy Technology Data Exchange (ETDEWEB)

    1967-11-30

    The design of a rotary core drill is described. Primary consideration is given to the following component parts of the drill: the inner and outer tube, the core bit, an adapter, and the core lifter. The adapter has the form of a downward-converging sleeve and is mounted to the lower end of the inner tube. The lifter, extending from the adapter, is split along each side so that it can be held open to permit movement of a core. It is possible to grip a core by allowing the lifter to assume a closed position.

  8. Events diary

    Science.gov (United States)

    2000-01-01

    as Imperial College, the Royal Albert Hall, the Royal College of Art, the Natural History and Science Museums and the Royal Geographical Society. Under the heading `Shaping the future together' BA2000 will explore science, engineering and technology in their wider cultural context. Further information about this event on 6 - 12 September may be obtained from Sandra Koura, BA2000 Festival Manager, British Association for the Advancement of Science, 23 Savile Row, London W1X 2NB (tel: 0171 973 3075, e-mail: sandra.koura@britassoc.org.uk ). Details of the creating SPARKS events may be obtained from creating.sparks@britassoc.org.uk or from the website www.britassoc.org.uk . Other events 3 - 7 July, Porto Alegre, Brazil VII Interamerican conference on physics education: The preparation of physicists and physics teachers in contemporary society. Info: IACPE7@if.ufrgs.br or cabbat1.cnea.gov.ar/iacpe/iacpei.htm 27 August - 1 September, Barcelona, Spain GIREP conference: Physics teacher education beyond 2000. Info: www.blues.uab.es/phyteb/index.html

  9. Design study on metal fuel FBR cores

    International Nuclear Information System (INIS)

    Yokoo, T.; Tanaka, Y.; Ogata, T.

    1991-01-01

    A design approach for metal fuel FBR core to maintain fuel integrity during transient events by limiting eutectic/liquid phase formation is proposed based on the current status of metallic fuel development. Its impact as the limitation on the core outlet temperature is assessed through its application to two of CRIEPI's core concepts, high linear power 1000 MWe homogeneous design and medium linear power 300 MWe radially heterogeneous design. SESAME/SALT code is used in this study to analyze steady state and transient fuel behavior. SE2-FA code is developed based on SUPERENERGY-2 and used to analyze core thermal-hydraulics with uncertainties. As the result, the core outlet temperatures of both designs are found to be limited to ≤500degC if it is required to prevent eutectic/liquid phase formation during operational transients in order to guarantee the fuel integrity. Additional assessment is made assuming an advanced limiting condition that allows small liquid phase formation based on the liquid phase penetration rate derived from existing experimental results. The result indicates possibility of raising core outlet temperature to ∼ 530degC. Also, it is found that core design technology improvements such as hot spot factors reduction can contribute to the core outlet temperature extension by 10 ∼ 20degC. (author)

  10. An assessment of the risk significance of human errors in selected PSAs and operating events

    International Nuclear Information System (INIS)

    Palla, R.L. Jr.; El-Bassioni, A.

    1991-01-01

    Sensitivity studies based on Probabilistic Safety Assessments (PSAs) for a pressurized water reactor and a boiling water reactor are described. In each case human errors modeled in the PSAs were categorized according to such factors as error type, location, timing, and plant personnel involved. Sensitivity studies were then conducted by varying the error rates in each category and evaluating the corresponding change in total core damage frequency and accident sequence frequency. Insights obtained are discussed and reasons for differences in risk sensitivity between plants are explored. A separate investigation into the role of human error in risk-important operating events is also described. This investigation involved the analysis of data from the USNRC Accident Sequence Precursor program to determine the effect of operator-initiated events on accident precursor trends, and to determine whether improved training can be correlated to current trends. The findings of this study are also presented. 5 refs., 15 figs., 1 tab

  11. Flood damage: a model for consistent, complete and multipurpose scenarios

    Science.gov (United States)

    Menoni, Scira; Molinari, Daniela; Ballio, Francesco; Minucci, Guido; Mejri, Ouejdane; Atun, Funda; Berni, Nicola; Pandolfo, Claudia

    2016-12-01

    Effective flood risk mitigation requires the impacts of flood events to be much better and more reliably known than is currently the case. Available post-flood damage assessments usually supply only a partial vision of the consequences of the floods as they typically respond to the specific needs of a particular stakeholder. Consequently, they generally focus (i) on particular items at risk, (ii) on a certain time window after the occurrence of the flood, (iii) on a specific scale of analysis or (iv) on the analysis of damage only, without an investigation of damage mechanisms and root causes. This paper responds to the necessity of a more integrated interpretation of flood events as the base to address the variety of needs arising after a disaster. In particular, a model is supplied to develop multipurpose complete event scenarios. The model organizes available information after the event according to five logical axes. This way post-flood damage assessments can be developed that (i) are multisectoral, (ii) consider physical as well as functional and systemic damage, (iii) address the spatial scales that are relevant for the event at stake depending on the type of damage that has to be analyzed, i.e., direct, functional and systemic, (iv) consider the temporal evolution of damage and finally (v) allow damage mechanisms and root causes to be understood. All the above features are key for the multi-usability of resulting flood scenarios. The model allows, on the one hand, the rationalization of efforts currently implemented in ex post damage assessments, also with the objective of better programming financial resources that will be needed for these types of events in the future. On the other hand, integrated interpretations of flood events are fundamental to adapting and optimizing flood mitigation strategies on the basis of thorough forensic investigation of each event, as corroborated by the implementation of the model in a case study.

  12. Geophysical events

    Science.gov (United States)

    This is a summary of SEAN Bulletin, 13(3), March 31, 1988, a publication of the Smithsonian Institution's Scientific Event Alert Network. The complete bulletin is available in the microfiche edition of Eos as a microfiche supplement or as a paper reprint. For the microfiche, order document E88-002 at $2.50 (U.S.) by writing to AGU Orders, 2000 Florida Avenue, N.W., Washington, DC 20009 or by calling toll free on 800-424-2488. For the paper reprint, order SEAN Bulletin (giving volume and issue numbers and issue date) through the same address; the price is $3.50 for one copy of each issue number for those who do not have a deposit account, $2 for those who do; additional copies of each issue number are $1. Subscriptions to SEAN Bulletin are also available from AGU-Orders; the price is $18 for 12 monthly issues mailed to a U.S. address, $28 if mailed elsewhere, and must be prepaid.

  13. Damage Localization and Quantification of Earthquake Excited RC-Frames

    DEFF Research Database (Denmark)

    Skjærbæk, P. S.; Nielsen, Søren R. K.; Kirkegaard, Poul Henning

    1998-01-01

    or three series of ground motions of increasing magnitude. After each of these runs the damage state of the frame was examined and each storey of the frame were classified into one of the following six classifications: undamaged, cracked, lightly damaged, damaged, severely damaged or collapse. During each...... of the ground motion events the storey accelerations were measured by accelerometers. After application of the last earthquake sequence to the structure the frames were cut into pieces and each of the beams and columns was statically tested and damage assessment was performed using the obtained stiffnesses...

  14. Profiling DNA damage response following mitotic perturbations

    DEFF Research Database (Denmark)

    Pedersen, Ronni Sølvhøi; Karemore, Gopal; Gudjonsson, Thorkell

    2016-01-01

    that a broad spectrum of mitotic errors correlates with increased DNA breakage in daughter cells. Unexpectedly, we find that only a subset of these correlations are functionally linked. We identify the genuine mitosis-born DNA damage events and sub-classify them according to penetrance of the observed...

  15. HYDRATE CORE DRILLING TESTS

    Energy Technology Data Exchange (ETDEWEB)

    John H. Cohen; Thomas E. Williams; Ali G. Kadaster; Bill V. Liddell

    2002-11-01

    The ''Methane Hydrate Production from Alaskan Permafrost'' project is a three-year endeavor being conducted by Maurer Technology Inc. (MTI), Noble, and Anadarko Petroleum, in partnership with the U.S. DOE National Energy Technology Laboratory (NETL). The project's goal is to build on previous and ongoing R&D in the area of onshore hydrate deposition. The project team plans to design and implement a program to safely and economically drill, core and produce gas from arctic hydrates. The current work scope includes drilling and coring one well on Anadarko leases in FY 2003 during the winter drilling season. A specially built on-site core analysis laboratory will be used to determine some of the physical characteristics of the hydrates and surrounding rock. Prior to going to the field, the project team designed and conducted a controlled series of coring tests for simulating coring of hydrate formations. A variety of equipment and procedures were tested and modified to develop a practical solution for this special application. This Topical Report summarizes these coring tests. A special facility was designed and installed at MTI's Drilling Research Center (DRC) in Houston and used to conduct coring tests. Equipment and procedures were tested by cutting cores from frozen mixtures of sand and water supported by casing and designed to simulate hydrate formations. Tests were conducted with chilled drilling fluids. Tests showed that frozen core can be washed out and reduced in size by the action of the drilling fluid. Washing of the core by the drilling fluid caused a reduction in core diameter, making core recovery very difficult (if not impossible). One successful solution was to drill the last 6 inches of core dry (without fluid circulation). These tests demonstrated that it will be difficult to capture core when drilling in permafrost or hydrates without implementing certain safeguards. Among the coring tests was a simulated hydrate

  16. Aspects of unconventional cores for large sodium cooled power reactors; evaluation of a literature survey

    International Nuclear Information System (INIS)

    Kiefhaber, E.

    1978-10-01

    The report gives an overview of a literature study on the application of unconventional cores for sodium cooled fast reactors. Different types of unconventional cores (heterogeneous cores, pancake cores, moderated cores and others) are compared with conventional cores, which are characterized by a cylindrical geometry with two or three fissile zones surrounded by an axial and a radial blanket. The main parameters of interest in this comparison are the neutronic parameters sodium void and Doppler effect, the breeding properties and the steel damage. Consequences for the core safety and the overall plant design are also mentioned

  17. Determination of PWR core water level using ex-core detectors signals

    International Nuclear Information System (INIS)

    Bernal, Alvaro; Abarca, Agustin; Miro, Rafael; Verdu, Gumersindo

    2013-01-01

    The core water level provides relevant neutronic and thermalhydraulic information of the reactor such as power, k eff and cooling ability; in fact, core water level monitoring could be used to predict LOCA and cooling reduction which may deal with core damage. Although different detection equipment is used to monitor several parameters such as the power, core water level monitoring is not an evident task. However, ex-core detectors can measure the fast neutrons leaking the core and several studies demonstrate the existence of a relationship between fast neutron leakage and core water level due to the shielding effect of the water. In addition, new ex-core detectors are being developed, such as silicon carbide semiconductor radiation detectors, monitoring the neutron flux with higher accuracy and in higher temperatures conditions. Therefore, a methodology to determine this relationship has been developed based on a Monte Carlo calculation using MCNP code and applying variance reduction with adjoint functions based on the adjoint flux obtained with the discrete ordinates code TORT. (author)

  18. Ultimate Electrical Means for Severe Accident and Multi Unit Event Management

    International Nuclear Information System (INIS)

    Guisez, Xavier

    2015-01-01

    Following the Multi Unit Severe Accident that occurred at Fukushima as a result of the tsunami on 11 March 2011, the European Council decided to submit its Nuclear Power Plants to a Stress Test. In Belgium, this Stress Test, named BEST (Belgian Stress Test), was successfully concluded at the end of 2011. Nevertheless, Electrabel decided, in agreement with the Authorities, to start a beyond design basis action plan, with the goal to mitigate the consequences of a Beyond Design Basis Accident and a Multi Unit Event. Consequently, this has led to an improvement of the robustness of its Nuclear Power Plants. Considering the importance of electrical power supply to a nuclear power plant, a significant part of this action plan consisted of setting up a mobile, 'plug and play' method for the electrical power supply to some major safety systems. In order to install this ultimate power supply, three factors were retained as essential. First, important reactor monitoring instrumentation is preserved. Second, core cooling is provided at all times. Finally, systems are easily made operational within a very short delay of time. During normal operation and Design Basis Events, core cooling is provided by High Voltage equipment. However, during high stress circumstances, it is too complex to realize connections on this equipment. Therefore, analysis was performed to realize core cooling with, easier to handle, Low Voltage equipment. These systems are powered by several GenSets, especially designed and manufactured for this application. The outcome of this project are easy to use, ultimate means, that supply electric power to important safety systems in order to drastically reduce the risk of core damage, during a beyond design basis event. Additionally, for all ultimate means, procedures and training modules were developed for the operators. (authors)

  19. Self-Healing Structural Materials for Damage Tolerant Aerospace Vehicles

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed  effort describes how to develop novel lightweight, self-healing systems where self-repair is induced by the forces imparted by the damage event itself....

  20. Radiation damage studies of nuclear structural materials

    International Nuclear Information System (INIS)

    Barat, P.

    2012-01-01

    Maximum utilization of fuel in nuclear reactors is one of the important aspects for operating them economically. The main hindrance to achieve this higher burnups of nuclear fuel for the nuclear reactors is the possibility of the failure of the metallic core components during their operation. Thus, the study of the cause of the possibility of failure of these metallic structural materials of nuclear reactors during full power operation due to radiation damage, suffered inside the reactor core, is an important field of studies bearing the basic to industrial scientific views.The variation of the microstructure of the metallic core components of the nuclear reactors due to radiation damage causes enormous variation in the structure and mechanical properties. A firm understanding of this variation of the mechanical properties with the variation of microstructure will serve as a guide for creating new, more radiation-tolerant materials. In our centre we have irradiated structural materials of Indian nuclear reactors by charged particles from accelerator to generate radiation damage and studied the some aspects of the variation of microstructure by X-ray diffraction studies. Results achieved in this regards, will be presented. (author)

  1. Nuclear reactor core modelling in multifunctional simulators

    International Nuclear Information System (INIS)

    Puska, E.K.

    1999-01-01

    The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been

  2. Nuclear reactor core modelling in multifunctional simulators

    Energy Technology Data Exchange (ETDEWEB)

    Puska, E.K. [VTT Energy, Nuclear Energy, Espoo (Finland)

    1999-06-01

    The thesis concentrates on the development of nuclear reactor core models for the APROS multifunctional simulation environment and the use of the core models in various kinds of applications. The work was started in 1986 as a part of the development of the entire APROS simulation system. The aim was to create core models that would serve in a reliable manner in an interactive, modular and multifunctional simulator/plant analyser environment. One-dimensional and three-dimensional core neutronics models have been developed. Both models have two energy groups and six delayed neutron groups. The three-dimensional finite difference type core model is able to describe both BWR- and PWR-type cores with quadratic fuel assemblies and VVER-type cores with hexagonal fuel assemblies. The one- and three-dimensional core neutronics models can be connected with the homogeneous, the five-equation or the six-equation thermal hydraulic models of APROS. The key feature of APROS is that the same physical models can be used in various applications. The nuclear reactor core models of APROS have been built in such a manner that the same models can be used in simulator and plant analyser applications, as well as in safety analysis. In the APROS environment the user can select the number of flow channels in the three-dimensional reactor core and either the homogeneous, the five- or the six-equation thermal hydraulic model for these channels. The thermal hydraulic model and the number of flow channels have a decisive effect on the calculation time of the three-dimensional core model and thus, at present, these particular selections make the major difference between a safety analysis core model and a training simulator core model. The emphasis on this thesis is on the three-dimensional core model and its capability to analyse symmetric and asymmetric events in the core. The factors affecting the calculation times of various three-dimensional BWR, PWR and WWER-type APROS core models have been

  3. ICPP criticality event of October 17, 1978. Facts and sequential description of criticality event and precursor events

    International Nuclear Information System (INIS)

    1979-01-01

    On October 17 during the period of approximately 8:15 to 8:40 p.m., a criticality event occurred in the base of IB column, H-100. The inventory of medium short-lived fission products used to determine the number of fissions indicates that the criticality occurred in column H-100 aqueous phase and the sampling of the column wall with counting of the filings clearly indicates that the event occurred in the column base. The events leading up to the accident are described. The event produced no personnel injury, on-or off-site contamination, nor damage to equipment or property

  4. Impact damage in aircraft composite sandwich panels

    Science.gov (United States)

    Mordasky, Matthew D.

    An experimental study was conducted to develop an improved understanding of the damage caused by runway debris and environmental threats on aircraft structures. The velocities of impacts for stationary aircraft and aircraft under landing and takeoff speeds was investigated. The impact damage by concrete, asphalt, aluminum, hail and rubber sphere projectiles was explored in detail. Additionally, a kinetic energy and momentum experimental study was performed to look at the nature of the impacts in more detail. A method for recording the contact force history of the impact by an instrumented projectile was developed and tested. The sandwich composite investigated was an IM7-8552 unidirectional prepreg adhered to a NOMEXRTM core with an FM300K film adhesive. Impact experiments were conducted with a gas gun built in-house specifically for delivering projectiles to a sandwich composite target in this specic velocity regime (10--140 m/s). The effect on the impact damage by the projectile was investigated by ultrasonic C-scan, high speed camera and scanning electron and optical microscopy. Ultrasonic C-scans revealed the full extent of damage caused by each projectile, while the high speed camera enabled precise projectile velocity measurements that were used for striking velocity, kinetic energy and momentum analyses. Scanning electron and optical images revealed specific features of the panel failure and manufacturing artifacts within the lamina and honeycomb core. The damage of the panels by different projectiles was found to have a similar damage area for equivalent energy levels, except for rubber which had a damage area that increased greatly with striking velocity. Further investigation was taken by kinetic energy and momentum based comparisons of 19 mm diameter stainless steel sphere projectiles in order to examine the dominating damage mechanisms. The sandwich targets were struck by acrylic, aluminum, alumina, stainless steel and tungsten carbide spheres of the

  5. The core paradox.

    Science.gov (United States)

    Kennedy, G. C.; Higgins, G. H.

    1973-01-01

    Rebuttal of suggestions from various critics attempting to provide an escape from the seeming paradox originated by Higgins and Kennedy's (1971) proposed possibility that the liquid in the outer core was thermally stably stratified and that this stratification might prove a powerful inhibitor to circulation of the outer core fluid of the kind postulated for the generation of the earth's magnetic field. These suggestions are examined and shown to provide no reasonable escape from the core paradox.

  6. Event Displays for the Visualization of CMS Events

    CERN Document Server

    Jones, Christopher Duncan

    2010-01-01

    During the last year the CMS experiment engaged in consolidation of its existing event display programs. The core of the new system is based on the Fireworks event display program which was by-design directly integrated with the CMS Event Data Model (EDM) and the light version of the software framework (FWLite). The Event Visualization Environment (EVE) of the ROOT framework is used to manage a consistent set of 3D and 2D views, selection, user-feedback and user-interaction with the graphics windows; several EVE components were developed by CMS in collaboration with the ROOT project. In event display operation simple plugins are registered into the system to perform conversion from EDM collections into their visual representations which are then managed by the application. Full event navigation and filtering as well as collection-level filtering is supported. The same data-extraction principle can also be applied when Fireworks will eventually operate as a service within the full software framework.

  7. Event Display for the Visualization of CMS Events

    Science.gov (United States)

    Bauerdick, L. A. T.; Eulisse, G.; Jones, C. D.; Kovalskyi, D.; McCauley, T.; Mrak Tadel, A.; Muelmenstaedt, J.; Osborne, I.; Tadel, M.; Tu, Y.; Yagil, A.

    2011-12-01

    During the last year the CMS experiment engaged in consolidation of its existing event display programs. The core of the new system is based on the Fireworks event display program which was by-design directly integrated with the CMS Event Data Model (EDM) and the light version of the software framework (FWLite). The Event Visualization Environment (EVE) of the ROOT framework is used to manage a consistent set of 3D and 2D views, selection, user-feedback and user-interaction with the graphics windows; several EVE components were developed by CMS in collaboration with the ROOT project. In event display operation simple plugins are registered into the system to perform conversion from EDM collections into their visual representations which are then managed by the application. Full event navigation and filtering as well as collection-level filtering is supported. The same data-extraction principle can also be applied when Fireworks will eventually operate as a service within the full software framework.

  8. Event Display for the Visualization of CMS Events

    International Nuclear Information System (INIS)

    Bauerdick, L A T; Eulisse, G; Jones, C D; McCauley, T; Osborne, I; Kovalskyi, D; Tadel, A Mrak; Muelmenstaedt, J; Tadel, M; Tu, Y; Yagil, A

    2011-01-01

    During the last year the CMS experiment engaged in consolidation of its existing event display programs. The core of the new system is based on the Fireworks event display program which was by-design directly integrated with the CMS Event Data Model (EDM) and the light version of the software framework (FWLite). The Event Visualization Environment (EVE) of the ROOT framework is used to manage a consistent set of 3D and 2D views, selection, user-feedback and user-interaction with the graphics windows; several EVE components were developed by CMS in collaboration with the ROOT project. In event display operation simple plugins are registered into the system to perform conversion from EDM collections into their visual representations which are then managed by the application. Full event navigation and filtering as well as collection-level filtering is supported. The same data-extraction principle can also be applied when Fireworks will eventually operate as a service within the full software framework.

  9. Nuclear reactor core flow baffling

    International Nuclear Information System (INIS)

    Berringer, R.T.

    1979-01-01

    A flow baffling arrangement is disclosed for the core of a nuclear reactor. A plurality of core formers are aligned with the grids of the core fuel assemblies such that the high pressure drop areas in the core are at the same elevations as the high pressure drop areas about the core periphery. The arrangement minimizes core bypass flow, maintains cooling of the structure surrounding the core, and allows the utilization of alternative beneficial components such as neutron reflectors positioned near the core

  10. RBMK-1500 accident management for loss of long-term core cooling

    International Nuclear Information System (INIS)

    Uspuras, E.; Kaliatka, A.

    2001-01-01

    Results of the Level 1 probabilistic safety assessment of the Ignalina NPP has shown that in topography of the risk, transients dominate above the accidents with LOCAs and failure of the core long-term cooling are the main factors to frequency of the core damage. Previous analyses have shown, that after initial event, as a rule, the reactivity control, as well as short-term and intermediate cooling are provided. However, the acceptance criteria of the long-term cooling are not always carried out. It means that from this point of view the most dangerous accident scenarios are the scenarios related to loss of the core long-term cooling. On the other hand, the transition to the core condition due to loss of the long-term cooling specifies potential opportunities for the management of the accident consequences. Hence, accident management for the mitigation of the accident consequences should be considered and developed. The most likely initiating event, which probably leads to the loss of long term cooling accident, is station blackout. The station blackout is the loss of normal electrical power supply for local needs with an additional failure on start-up of all diesel generators. In the case of loss of electrical power supply MCPs, the circulating pumps of the service water system and MFWPs are switched-off. At the same time, TCV of both turbines are closed. Failure of diesel generators leads to the non-operability of the ECCS long-term cooling subsystem. It means the impossibility to feed MCC by water. The analysis of the station blackout for Ignalina NPP was performed using RELAP5 code. (author)

  11. Sediment Core Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides instrumentation and expertise for physical and geoacoustic characterization of marine sediments.DESCRIPTION: The multisensor core logger measures...

  12. Failure Mode and Effects Analysis (FMEA) of the Emergency Core Cooling System (ECCS) for a Westinghouse type 312, three loop pressurized water reactor

    International Nuclear Information System (INIS)

    Shopsky, W.E.

    1977-01-01

    The Emergency Core Cooling System (ECCS) is a Safeguards System designed to cool the core in the unlikely event of a Loss-of-Coolant Accident (LOCA) in the primary reactor coolant system as well as to provide additional shutdown capability following a steam break accident. The system is designed for a high reliability of providing emergency coolant and shutdown reactivity to the core for all anticipated occurrences of such accidents. The ECCS by performing its intended function assures that fuel and clad damage is minimized during accident conditions thus reducing release of fission products from the fuel. The ECCS is designed to perform its function despite sustaining a single failure by the judicious use of equipment and flow path redundancy within and outside the containment structure. By the use of an analytic tool, a Failure Mode and Effects Analysis (FMEA), it is shown that the ECCS is in compliance with the Single Failure Criterion established for active failures of fluid systems during short and long term cooling of the reactor core following a LOCA or steam break accident. An analysis was also performed with regards to passive failure of ECCS components during long-term cooling of the core following an accident. The design of the ECCS was verified as being able to tolerate a single passive failure during long-term cooling of the reactor core following an accident. The FMEA conducted qualitatively demonstrates the reliability of the ECCS (concerning active components) to perform its intended safety function

  13. Treatment of Events Representing System Success in Accident Sequences in PSA Models with ET/FT Linking

    International Nuclear Information System (INIS)

    Vrbanic, I.; Spiler, J.; Mikulicic, V.; Simic, Z.

    2002-01-01

    Treatment of events that represent systems' successes in accident sequences is well known issue associated primarily with those PSA models that employ event tree / fault tree (ET / FT) linking technique. Even theoretically clear, practical implementation and usage creates for certain PSA models a number of difficulties regarding result correctness. Strict treatment of success-events would require consistent applying of de Morgan laws. However, there are several problems related to it. First, Boolean resolution of the overall model, such as the one representing occurrence of reactor core damage, becomes very challenging task if De Morgan rules are applied consistently at all levels. Even PSA tools of the newest generation have some problems with performing such a task in a reasonable time frame. The second potential issue is related to the presence of negated basic events in minimal cutsets. If all the basic events that result from strict applying of De Morgan rules are retained in presentation of minimal cutsets, their readability and interpretability may be impaired severely. It is also worth noting that the concept of a minimal cutset is tied to equipment failures, rather than to successes. For reasons like these, various simplifications are employed in PSA models and tools, when it comes to the treatment of success-events in the sequences. This paper provides a discussion of major concerns associated with the treatment of success-events in accident sequences of a typical PSA model. (author)

  14. Can Psychiatric Rehabilitation Be Core to CORE?

    Science.gov (United States)

    Olney, Marjorie F.; Gill, Kenneth J.

    2016-01-01

    Purpose: In this article, we seek to determine whether psychiatric rehabilitation principles and practices have been more fully incorporated into the Council on Rehabilitation Education (CORE) standards, the extent to which they are covered in four rehabilitation counseling "foundations" textbooks, and how they are reflected in the…

  15. Event and fault tree model for reliability analysis of the greek research reactor

    International Nuclear Information System (INIS)

    Albuquerque, Tob R.; Guimaraes, Antonio C.F.; Moreira, Maria de Lourdes

    2013-01-01

    Fault trees and event trees are widely used in industry to model and to evaluate the reliability of safety systems. Detailed analyzes in nuclear installations require the combination of these two techniques. This work uses the methods of fault tree (FT) and event tree (ET) to perform the Probabilistic Safety Assessment (PSA) in research reactors. The PSA according to IAEA (International Atomic Energy Agency) is divided into Level 1, Level 2 and level 3. At Level 1, conceptually safety systems act to prevent the accident, at Level 2, the accident occurred and seeks to minimize the consequences, known as stage management of the accident, and at Level 3 are determined consequences. This paper focuses on Level 1 studies, and searches through the acquisition of knowledge consolidation of methodologies for future reliability studies. The Greek Research Reactor, GRR - 1, was used as a case example. The LOCA (Loss of Coolant Accident) was chosen as the initiating event and from there were developed the possible accident sequences, using event tree, which could lead damage to the core. Furthermore, for each of the affected systems, the possible accidents sequences were made fault tree and evaluated the probability of each event top of the FT. The studies were conducted using a commercial computational tool SAPHIRE. The results thus obtained, performance or failure to act of the systems analyzed were considered satisfactory. This work is directed to the Greek Research Reactor due to data availability. (author)

  16. Event and fault tree model for reliability analysis of the greek research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, Tob R.; Guimaraes, Antonio C.F.; Moreira, Maria de Lourdes, E-mail: atalbuquerque@ien.gov.br, E-mail: btony@ien.gov.br, E-mail: malu@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Fault trees and event trees are widely used in industry to model and to evaluate the reliability of safety systems. Detailed analyzes in nuclear installations require the combination of these two techniques. This work uses the methods of fault tree (FT) and event tree (ET) to perform the Probabilistic Safety Assessment (PSA) in research reactors. The PSA according to IAEA (International Atomic Energy Agency) is divided into Level 1, Level 2 and level 3. At Level 1, conceptually safety systems act to prevent the accident, at Level 2, the accident occurred and seeks to minimize the consequences, known as stage management of the accident, and at Level 3 are determined consequences. This paper focuses on Level 1 studies, and searches through the acquisition of knowledge consolidation of methodologies for future reliability studies. The Greek Research Reactor, GRR - 1, was used as a case example. The LOCA (Loss of Coolant Accident) was chosen as the initiating event and from there were developed the possible accident sequences, using event tree, which could lead damage to the core. Furthermore, for each of the affected systems, the possible accidents sequences were made fault tree and evaluated the probability of each event top of the FT. The studies were conducted using a commercial computational tool SAPHIRE. The results thus obtained, performance or failure to act of the systems analyzed were considered satisfactory. This work is directed to the Greek Research Reactor due to data availability. (author)

  17. Radiation damage to mushrooms

    International Nuclear Information System (INIS)

    Sattler, P.W.

    1986-01-01

    This document contains newspaper cuttings and correspondence with various ministries in Hessen on the subject of radiation damage to mushrooms from the Odenwald area. The reader is given, amongst other things, detailed information on radiation damage to different types of mushroom in 1986. (MG) [de

  18. Animal damage to birch

    Science.gov (United States)

    James S. Jordan; Francis M. Rushmore

    1969-01-01

    A relatively few animal species are responsible for most of the reported damage to the birches. White-tailed deer, yellow-bellied sapsuckers, porcupines, moose, and hares are the major animals involved. We will review reports of damage, discuss the underlying causes, and describe possible methods of control. For example, heavy deer browsing that eliminates birch...

  19. Animal damage management handbook.

    Science.gov (United States)

    Hugh C. Black

    1994-01-01

    This handbook treats animal damage management (ADM) in the West in relation to forest, range, and recreation resources; predator management is not addressed. It provides a comprehensive reference of safe, effective, and practical methods for managing animal damage on National Forest System lands. Supporting information is included in references after each chapter and...

  20. Nuclear damage - civil liability

    International Nuclear Information System (INIS)

    Simoes, A.C.

    1980-01-01

    An analysis is made of the civil liability for nuclear damage since there is a need to adjust the existing rules to the new situations created. The conventions that set up the new disciplining rules not considered in the common law for the liability of nuclear damage are also mentioned. (A.L.) [pt

  1. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

    2011-01-01

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  2. Guide line for operator in beyond design basis events for AHWR

    International Nuclear Information System (INIS)

    Kumar, Mithilesh; Mukhopadhyay, D.; Lele, H.G.; Vaze, K.K.

    2011-01-01

    Enhanced defence-in-depth is incorporated in the proposed Advanced Heavy Water Reactor (AHWR) as a part of their fundamental safety approach to ensure that the levels of protection in defence-in-depth shall be more independent from each other than in existing installation. Safety is enhanced by incorporating into their designs, increased emphasis on inherently safe characteristics and passive systems as a part of their fundamental safety approach. It is ensured that the risk from radiation exposures to workers, the public and the environment during construction/commissioning, operation, and decommissioning, shall be comparable to that of other industrial facilities used for similar purposes. This implies that there will be no need for relocation or evacuation measures outside the plant site, apart from those generic emergency measures developed for any industrial facility. It has been demonstrated by analyses that there is no core damage for PIEs with frequencies more than 10- 10 /year. However some scenarios in residual risk domain are considered to demonstrate that dose at plant boundary is within prescribed acceptable limit. It is also possible to arrest core damage progression at various stages of event progression, by incorporating certain operating procedures, without any release. This paper discusses analyses of such low frequency event with multiple failure under the category of 'Decrease in MHT inventory' where plant related symptoms like channel exit temperature, channel component temperatures, moderator level etc. with respect to time are quantified. The operator guide line has been given for case like Loss of coolant without Emergency core coolant system (ECCS) and loss moderator heat sink. It has been observed that 3.0 kg/s mass flow rate is adequate to capture the rising trend of clad surface temperature. (author)

  3. PWR core design calculations

    International Nuclear Information System (INIS)

    Trkov, A.; Ravnik, M.; Zeleznik, N.

    1992-01-01

    Functional description of the programme package Cord-2 for PWR core design calculations is presented. Programme package is briefly described. Use of the package and calculational procedures for typical core design problems are treated. Comparison of main results with experimental values is presented as part of the verification process. (author) [sl

  4. Replaceable LMFBR core components

    International Nuclear Information System (INIS)

    Evans, E.A.; Cunningham, G.W.

    1976-01-01

    Much progress has been made in understanding material and component performance in the high temperature, fast neutron environment of the LMFBR. Current data have provided strong assurance that the initial core component lifetime objectives of FFTF and CRBR can be met. At the same time, this knowledge translates directly into the need for improved core designs that utilize improved materials and advanced fuels required to meet objectives of low doubling times and extended core component lifetimes. An industrial base for the manufacture of quality core components has been developed in the US, and all procurements for the first two core equivalents for FFTF will be completed this year. However, the problem of fabricating recycled plutonium while dramatically reducing fabrication costs, minimizing personnel exposure, and protecting public health and safety must be addressed

  5. Lunar Core and Tides

    Science.gov (United States)

    Williams, J. G.; Boggs, D. H.; Ratcliff, J. T.

    2004-01-01

    Variations in rotation and orientation of the Moon are sensitive to solid-body tidal dissipation, dissipation due to relative motion at the fluid-core/solid-mantle boundary, and tidal Love number k2 [1,2]. There is weaker sensitivity to flattening of the core-mantle boundary (CMB) [2,3,4] and fluid core moment of inertia [1]. Accurate Lunar Laser Ranging (LLR) measurements of the distance from observatories on the Earth to four retroreflector arrays on the Moon are sensitive to lunar rotation and orientation variations and tidal displacement