WorldWideScience

Sample records for backfitting

  1. Consistency and asymptotic normality of profilekernel and backfitting estimators in semiparametric reproductive dispersion nonlinear models

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Semiparametric reproductive dispersion nonlinear model (SRDNM) is an extension of nonlinear reproductive dispersion models and semiparametric nonlinear regression models, and includes semiparametric nonlinear model and semiparametric generalized linear model as its special cases. Based on the local kernel estimate of nonparametric component, profile-kernel and backfitting estimators of parameters of interest are proposed in SRDNM, and theoretical comparison of both estimators is also investigated in this paper. Under some regularity conditions, strong consistency and asymptotic normality of two estimators are proved. It is shown that the backfitting method produces a larger asymptotic variance than that for the profile-kernel method. A simulation study and a real example are used to illustrate the proposed methodologies.

  2. Modification and backfitting at the Barsebaeck Nuclear Power Plant Unit 1 and 2 in safety related systems

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Leif [KSU, Nykoeping (Sweden); Nilsson, Ove; Lidh, B. [ES-Konsult AB, Stockholm (Sweden)

    1995-05-01

    This report is intended for use by the Swedish Nuclear Power Inspectorate. It has been published to enable comparison of modification and backfitting implemented at Barsebaeck, with those implemented at other plants, both domestic and abroad. The report summarizes the more notable modifications and backfitting carried out on any safety-related equipment, or software, at Barsebaeck, and covers the decade 1984 to 1994. Modifications to hardware, and to some extent to software, are catalogued, but not described in any detail. No general procedures (operational or maintenance) are dealt with. 3 refs.

  3. Consistency and asymptotic normality of profile-kernel and backfitting estimators in semiparametric reproductive dispersion nonlinear models

    Institute of Scientific and Technical Information of China (English)

    TANG NianSheng; CHEN XueDong; WANG XueRen

    2009-01-01

    Semiparametric reproductive dispersion nonlinear model (SRDNM) is an extension of nonlinear reproductive dispersion models and semiparametric nonlinear regression models, and includes semiparametric nonlinear model and semiparametric generalized linear model as its special cases. Based on the local kernel estimate of nonparametric component, profile-kernel and backfitting estimators of parameters of interest are proposed in SRDNM, and theoretical comparison of both estimators is also investigated in this paper. Under some regularity conditions, strong consistency and asymptotic normality of two estimators are proved. It is shown that the backtitting method produces a larger asymptotic variance than that for the profile-kernel method. A simulation study and a real example are used to illustrate the proposed methodologies.

  4. LWR design decision methodology: Phase II. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1981-01-01

    Techniques were identified to augment existing design process at the component and system level in order to optimize cost and safety between alternative system designs. The method was demonstrated using the Surry Low Pressure Injection System (LPIS). Three possible backfit options were analyzed for the Surry LPIS, assessing the safety level of each option and estimating the acquisition and installation costs for each. (DLC)

  5. Development of procedural requirements for life extension of nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hun; Son, Moon Kyu [Korea Association for Nuclear Technology, Taejon (Korea, Republic of); Ham, Cheol Hun [The Catholic University of Korea, Seoul (Korea, Republic of); Chang, Keun Sun [Sunmoon Univ., Asan (Korea, Republic of); Paek, Won Phil [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Cheong, Ji Hwan [Baekseok College Cultural Studies, Cheonan (Korea, Republic of)

    2001-03-15

    Current status of regulatory aspects of life extension and upgrading of NPPs is reviewed for major foreign countries. Most countries require similar technical requirements; however, procedural aspects differ country by country. Regulatory systems suitable for NPP life extension is investigated. The procedure and requirements for reassessment of design life should be established first; then it can be incorporated into the PSR system. The concept of 'Current Licensing Basis (CLB)' can be adopted in Korea, but further elaboration for terms and definitions is needed for common understanding between interested groups. The procedure for maintenance and backfitting should also be improved. The Systems, Structures, and Components (SSCs) that require development of regulatory requirements for life extension are identified based on extensive analysis of foreign experiences. By analyzing the rules and regulations related to life extension. Basic directions are suggested to harmonize or establish regulatory systems for life extension, two-step licensing, PSR, and backfitting.

  6. Nonparametric additive regression for repeatedly measured data

    KAUST Repository

    Carroll, R. J.

    2009-05-20

    We develop an easily computed smooth backfitting algorithm for additive model fitting in repeated measures problems. Our methodology easily copes with various settings, such as when some covariates are the same over repeated response measurements. We allow for a working covariance matrix for the regression errors, showing that our method is most efficient when the correct covariance matrix is used. The component functions achieve the known asymptotic variance lower bound for the scalar argument case. Smooth backfitting also leads directly to design-independent biases in the local linear case. Simulations show our estimator has smaller variance than the usual kernel estimator. This is also illustrated by an example from nutritional epidemiology. © 2009 Biometrika Trust.

  7. Measures for noise pollution abatement in existing cooling tower systems; Massnahmen zur Geraeuschminderung an bestehenden Kuehlturmanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Niessen, R. [Sulzer-Escher Wyss GmbH, Lindau (Germany)

    1998-09-01

    The operator`s order discussed by the paper was for planning and performance of backfitting measures for noise pollution abatement in an existing cooling tower system equipped with sound attenuation devices. Although the existing plant was operating in compliance with the legal noise emission limits, residents of neighbouring dwellings had been complaining about noise pollution. (orig./CB) [Deutsch] Die Aufgabe, eine nachtraegliche Massnahme zur Laermminderung an einer bestehenden, mit Schalldaempfern ausgeruesteten Anlage zu planen und durchzufuehren, wurde vom Betreiber einer Rueckkuehlanlage gestellt. Der vom Gesetzgeber definierte Grenzwert fuer den Nachtbetrieb wurde mit der bestehenden Anlage zwar erreicht, doch die Anwohner fuehlten eine Belaestigung durch den Anlagenbetrieb. (orig./GL)

  8. Model averaging for semiparametric additive partial linear models

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    To improve the prediction accuracy of semiparametric additive partial linear models(APLM) and the coverage probability of confidence intervals of the parameters of interest,we explore a focused information criterion for model selection among ALPM after we estimate the nonparametric functions by the polynomial spline smoothing,and introduce a general model average estimator.The major advantage of the proposed procedures is that iterative backfitting implementation is avoided,which thus results in gains in computational simplicity.The resulting estimators are shown to be asymptotically normal.A simulation study and a real data analysis are presented for illustrations.

  9. EFFICIENT ESTIMATION OF FUNCTIONAL-COEFFICIENT REGRESSION MODELS WITH DIFFERENT SMOOTHING VARIABLES

    Institute of Scientific and Technical Information of China (English)

    Zhang Riquan; Li Guoying

    2008-01-01

    In this article, a procedure for estimating the coefficient functions on the functional-coefficient regression models with different smoothing variables in different co-efficient functions is defined. First step, by the local linear technique and the averaged method, the initial estimates of the coefficient functions are given. Second step, based on the initial estimates, the efficient estimates of the coefficient functions are proposed by a one-step back-fitting procedure. The efficient estimators share the same asymptotic normalities as the local linear estimators for the functional-coefficient models with a single smoothing variable in different functions. Two simulated examples show that the procedure is effective.

  10. Efficient Quantile Estimation for Functional-Coefficient Partially Linear Regression Models

    Institute of Scientific and Technical Information of China (English)

    Zhangong ZHOU; Rong JIANG; Weimin QIAN

    2011-01-01

    The quantile estimation methods are proposed for functional-coefficient partially linear regression (FCPLR) model by combining nonparametric and functional-coefficient regression (FCR) model.The local linear scheme and the integrated method are used to obtain local quantile estimators of all unknown functions in the FCPLR model.These resulting estimators are asymptotically normal,but each of them has big variance.To reduce variances of these quantile estimators,the one-step backfitting technique is used to obtain the efficient quantile estimators of all unknown functions,and their asymptotic normalities are derived.Two simulated examples are carried out to illustrate the proposed estimation methodology.

  11. On concurvity in nonlinear and nonparametric regression models

    Directory of Open Access Journals (Sweden)

    Sonia Amodio

    2014-12-01

    Full Text Available When data are affected by multicollinearity in the linear regression framework, then concurvity will be present in fitting a generalized additive model (GAM. The term concurvity describes nonlinear dependencies among the predictor variables. As collinearity results in inflated variance of the estimated regression coefficients in the linear regression model, the result of the presence of concurvity leads to instability of the estimated coefficients in GAMs. Even if the backfitting algorithm will always converge to a solution, in case of concurvity the final solution of the backfitting procedure in fitting a GAM is influenced by the starting functions. While exact concurvity is highly unlikely, approximate concurvity, the analogue of multicollinearity, is of practical concern as it can lead to upwardly biased estimates of the parameters and to underestimation of their standard errors, increasing the risk of committing type I error. We compare the existing approaches to detect concurvity, pointing out their advantages and drawbacks, using simulated and real data sets. As a result, this paper will provide a general criterion to detect concurvity in nonlinear and non parametric regression models.

  12. Facades: PE building sites of the future?; Fassaden: PV-Bauplaetze der Zukunft?

    Energy Technology Data Exchange (ETDEWEB)

    Lippitsch, O. [KELAG-Kaerntner Elektrizitaets-AG, Klagenfurt (Austria); Friess, M. [Siemens AG Oesterreich, Wien (Austria)

    1996-12-01

    In order to limit the area used by the photo-electric use of solar energy, idle areas such as roofs and facades should be used. As backfitting is connected with high costs, solutions with integrated weather protection and energy obtention functions are favoured. Starting from an analysis of the stock of areas, the technical concept of the KELAG facade is described. (HW) [Deutsch] Um den Flaechenverbrauch bei der photovoltaischen Nutzung der Solarenergie einzuschraenken, sollten brachliegende Flaechen wie Daecher und Fassaden genutzt werden. Da die nachtraegliche Anbringung mit hohen Kosten verbunden ist, werden Loesungen mit integrierter Wetterschutz- und Energiegewinnungsfunktion favorisiert. Ausgehend von einer Flaechenbestandsanalyse wird die technische Konzeption der Kelag-Fassade dargestellt. (HW)

  13. Nuclear criticality safety department training implementation

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, K.J.; Taylor, R.G.; Worley, C.A.

    1996-09-06

    The Nuclear Criticality Safety Department (NCSD) is committed to developing and maintaining a staff of qualified personnel to meet the current and anticipated needs in Nuclear Criticality Safety (NCS) at the Oak Ridge Y-12 Plant. The NCSD Qualification Program is described in Y/DD-694, Qualification Program, Nuclear Criticality Safety Department This document provides a listing of the roles and responsibilities of NCSD personnel with respect to training and details of the Training Management System (TMS) programs, Mentoring Checklists and Checksheets, as well as other documentation utilized to implement the program. This document supersedes Y/DD-696, Revision 2, dated 3/27/96, Training Implementation, Nuclear Criticality Safety Department. There are no backfit requirements associated with revisions to this document.

  14. Evaluation of severe accident risks and the potential for risk reduction: Surry Power Station, Unit 1: Draft report for comment

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin, A.S.; Boyd, G.J.; Kunsman, D.M.; Murfin, W.B.; Williams, D.C.

    1987-02-01

    The Severe Accident Risk Reduction Program (SARRP) has completed a rebaselining of the risks to the public from a particular pressurized water reactor with a subatmospheric containment (Surry, Unit 1). Emphasis was placed on determining the magnitude and character of the uncertainties, rather than focusing on a point estimate. The risk-reduction potential of a set of proposed safety option backfits was also studied, and their costs and benefits were also evaluated. It was found that the risks from internal events are generally lower than previously evaluated in the Reactor Safety Study (RSS). However, certain unresolved issues (such as direct containment heating) caused the top of the uncertainty band to appear at a level that is comparable with the RSS point estimate. None of the postulated safety options appears to be cost effective for the Surry power plant. This work supports the Nuclear Regulatory Commission's assessment of severe accidents in NUREG-1150.

  15. LOFT Augmented Operator Capability Program

    Energy Technology Data Exchange (ETDEWEB)

    Hollenbeck, D.A.; Krantz, E.A.; Hunt, G.L.; Meyer, O.R.

    1980-01-01

    The outline of the LOFT Augmented Operator Capability Program is presented. This program utilizes the LOFT (Loss-of-Fluid Test) reactor facility which is located at the Idaho National Engineering Laboratory and the LOFT operational transient experiment series as a test bed for methods of enhancing the reactor operator's capability for safer operation. The design of an Operational Diagnotics and Display System is presented which was backfit to the existing data acquisition computers. Basic color-graphic displays of the process schematic and trend type are presented. In addition, displays were developed and are presented which represent safety state vector information. A task analysis method was applied to LOFT reactor operating procedures to test its usefulness in defining the operator's information needs and workload.

  16. Safeguards and retrievability from waste forms

    Energy Technology Data Exchange (ETDEWEB)

    Danker, W.

    1996-05-01

    This report describes issues discussed at a session from the PLutonium Stabilization and Immobilization Workshop related to safeguards and retrievability from waste forms. Throughout the discussion, the group probed the goals of disposition efforts, particularly an understanding of the {open_quotes}spent fuel standard{close_quotes}, since the disposition material form derives from these goals. The group felt strongly that not only the disposition goals but safeguards to meet these goals could affect the material form. Accordingly, the Department was encouraged to explore and apply safeguards as early in the implementation process as possible. It was emphasized that this was particularly true for any planned use of existing facilities. It is much easier to build safeguards approaches into the development of new facilities, than to backfit existing facilities. Accordingly, special safeguards challenges are likely to be encountered, given the cost and schedule advantages offered by use of existing facilities.

  17. Gradient Plasticity Model and its Implementation into MARMOT

    Energy Technology Data Exchange (ETDEWEB)

    Barker, Erin I.; Li, Dongsheng; Zbib, Hussein M.; Sun, Xin

    2013-08-01

    The influence of strain gradient on deformation behavior of nuclear structural materials, such as boby centered cubic (bcc) iron alloys has been investigated. We have developed and implemented a dislocation based strain gradient crystal plasticity material model. A mesoscale crystal plasticity model for inelastic deformation of metallic material, bcc steel, has been developed and implemented numerically. Continuum Dislocation Dynamics (CDD) with a novel constitutive law based on dislocation density evolution mechanisms was developed to investigate the deformation behaviors of single crystals, as well as polycrystalline materials by coupling CDD and crystal plasticity (CP). The dislocation density evolution law in this model is mechanism-based, with parameters measured from experiments or simulated with lower-length scale models, not an empirical law with parameters back-fitted from the flow curves.

  18. Application of the Vertex Exchange Method to estimate a semi-parametric mixture model for the MIC density of Escherichia coli isolates tested for susceptibility against ampicillin.

    Science.gov (United States)

    Jaspers, Stijn; Verbeke, Geert; Böhning, Dankmar; Aerts, Marc

    2016-01-01

    In the last decades, considerable attention has been paid to the collection of antimicrobial resistance data, with the aim of monitoring non-wild-type isolates. This monitoring is performed based on minimum inhibition concentration (MIC) values, which are collected through dilution experiments. We present a semi-parametric mixture model to estimate the entire MIC density on the continuous scale. The parametric first component is extended with a non-parametric second component and a new back-fitting algorithm, based on the Vertex Exchange Method, is proposed. Our data example shows how to estimate the MIC density for Escherichia coli tested for ampicillin and how to use this estimate for model-based classification. A simulation study was performed, showing the promising behavior of the new method, both in terms of density estimation as well as classification.

  19. Environmental information systems - practicable decision aids. Umweltinformationssysteme - praktikable Entscheidungshilfen

    Energy Technology Data Exchange (ETDEWEB)

    1988-01-01

    Environmental information systems are classified in documentation systems and environmental planning systems. In environmental information systems emphasis is laid on scientific documentation. Environmental planning systems, on the other hand, involve facts on the state of the environment with respect to the air, noise, water, soil, waste management, the ecology and nature conservation. They can be used as instruments for documenting trends in enviromental pollution and the state of the art in environmental engineering. The relation polluter-environment-enforcement plays a central role for the protection of the environment (integration in terms of the KMSYS). The 'trade and process-specific emissions' system already represents an instrument for the transfer of knowledge in the field of air pollution abatement (see, e.g., Clean Air Technical Code, and the backfitting of existing plants). (DG).

  20. SEMİPARAMETRİK REGRESYON

    Directory of Open Access Journals (Sweden)

    Münevver TURANLI

    2011-01-01

    Full Text Available SEMIPARAMETRIC REGRESSIONAbstract: Classical (parametric regression techniques are based on the assumption that the independent variable is correlated linearly with the dependent variables and the pattern of this relation is known. When such assumption cannot be verified, parameter estimations fail to be reliable. In cases where the way of correlation is not known or it does not comply with the known parametric mathematical patterns, nonparametric regression techniques are to be applied. One shortcoming concerning this procedure emerges particularly in the interpretation process due to problems brought about by multidimensional aspect of the existence of more than one independent variable. Whenever confronted with a case that includes more than one independent variable, some of the independent variables correlate linearly with the dependent variable; at other times some of the independent variables might correlate nonlinearly. In order to establish a modeling for such relations, semiparametric regression models, comprising the aggregate of parametric and nonparametric regression function, are utilized. İn this study semiparametric regression definitions, estimation (backfitting algorithm, confidence bands, calculating standard errors and hypothesis testing are explained.Keywords: Additive Models, Semiparametric Regression, Backfitting Algorithm.SEMİPARAMETRİK REGRESYONÖzet: Klasik (parametrik regresyon teknikleri, bağımlı değişkenin bağımsız değişkenlerle doğrusal bir ilişki içerisinde olduğunu ve ilişkinin şeklinin biliniyor olduğunu varsayar. Bu varsayımların sağlanamaması durumunda ise parametre tahminleri güvenilir olmamaktadır. İlişkinin şeklinin bilinmediği ya da bilinen parametrik matamatiksel kalıplara uymadığı durumlarda parametrik olmayan regresyon teknikleri kullanılmaktadır. Ancak bu teknikler birden fazla bağımsız değişken olma durumunda çok boyutluluğun yarattığı sıkıntı nedeniyle

  1. Action plan Fukushima 2013; Aktionsplan Fukushima 2013

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    As a direct consequence of the accident at the nuclear power plant (NPP) at Fukushima Dai-ichi in Japan in March 2011, the Swiss Federal Nuclear Safety Inspectorate (ENSI) opened measures to check the safety of the Swiss NPPs. In the first 3 orders the operators of the Swiss NPPs were required to implement immediate measures and to conduct additional reassessments. The immediate measures comprised the establishment of an external emergency storage facility for the Swiss NPPs, including the necessary plant-specific connections, and back-fittings to provide external injection into the spent fuel pools. The additional reassessments focused on the design of the Swiss NPPs against earthquakes, external flooding and a combination thereof. Investigations on the coolant supply for the safety systems and the spent fuel pool cooling on the basis of first insights gained from the accident in Japan were also requested. Parallel to the operators' checks ENSI conducted inspections in order to detect eventual weaknesses in the cooling systems of the fuel element storage pools, the protection against external flooding and the systems for filtered depressurization of the containment. The inspections were pursued in 2012 and included the plant strategy in the case of a long-term loss of the power supply, the process and guides for the evaluation of external events and the available emergency premises in the Swiss NPPs. The results of the ENSI's inspections have confirmed that the Swiss NPPs show a high protection against the effects of earthquakes, flooding and combination thereof, and that appropriate measures against the loss of power supply and heat sink have been taken. All analysed accidents can be mastered under taking into account the actual safety measures. So the legal requirements for the respect of the protection goals, i.e. reactivity control, cooling of the fuel elements and enclosing of radioactive materials, are guaranteed. In view to an improvement of the

  2. Nonparametric modeling and analysis of association between Huntington's disease onset and CAG repeats.

    Science.gov (United States)

    Ma, Yanyuan; Wang, Yuanjia

    2014-04-15

    Huntington's disease (HD) is a neurodegenerative disorder with a dominant genetic mode of inheritance caused by an expansion of CAG repeats on chromosome 4. Typically, a longer sequence of CAG repeat length is associated with increased risk of experiencing earlier onset of HD. Previous studies of the association between HD onset age and CAG length have favored a logistic model, where the CAG repeat length enters the mean and variance components of the logistic model in a complex exponential-linear form. To relax the parametric assumption of the exponential-linear association to the true HD onset distribution, we propose to leave both mean and variance functions of the CAG repeat length unspecified and perform semiparametric estimation in this context through a local kernel and backfitting procedure. Motivated by including family history of HD information available in the family members of participants in the Cooperative Huntington's Observational Research Trial (COHORT), we develop the methodology in the context of mixture data, where some subjects have a positive probability of being risk free. We also allow censoring on the age at onset of disease and accommodate covariates other than the CAG length. We study the theoretical properties of the proposed estimator and derive its asymptotic distribution. Finally, we apply the proposed methods to the COHORT data to estimate the HD onset distribution using a group of study participants and the disease family history information available on their family members.

  3. Handbook for quick cost estimates. A method for developing quick approximate estimates of costs for generic actions for nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ball, J.R.

    1986-04-01

    This document is a supplement to a ''Handbook for Cost Estimating'' (NUREG/CR-3971) and provides specific guidance for developing ''quick'' approximate estimates of the cost of implementing generic regulatory requirements for nuclear power plants. A method is presented for relating the known construction costs for new nuclear power plants (as contained in the Energy Economic Data Base) to the cost of performing similar work, on a back-fit basis, at existing plants. Cost factors are presented to account for variations in such important cost areas as construction labor productivity, engineering and quality assurance, replacement energy, reworking of existing features, and regional variations in the cost of materials and labor. Other cost categories addressed in this handbook include those for changes in plant operating personnel and plant documents, licensee costs, NRC costs, and costs for other government agencies. Data sheets, worksheets, and appropriate cost algorithms are included to guide the user through preparation of rough estimates. A sample estimate is prepared using the method and the estimating tools provided.

  4. Regulatory analysis technical evaluation handbook. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-01-01

    The purpose of this Handbook is to provide guidance to the regulatory analyst to promote preparation of quality regulatory analysis documents and to implement the policies of the Regulatory Analysis Guidelines of the US Nuclear Regulatory Commission (NUREG/BR-0058 Rev. 2). This Handbook expands upon policy concepts included in the NRC Guidelines and translates the six steps in preparing regulatory analyses into implementable methodologies for the analyst. It provides standardized methods of preparation and presentation of regulatory analyses, with the inclusion of input that will satisfy all backfit requirements and requirements of NRC`s Committee to Review Generic Requirements. Information on the objectives of the safety goal evaluation process and potential data sources for preparing a safety goal evaluation is also included. Consistent application of the methods provided here will result in more directly comparable analyses, thus aiding decision-makers in evaluating and comparing various regulatory actions. The handbook is being issued in loose-leaf format to facilitate revisions. NRC intends to periodically revise the handbook as new and improved guidance, data, and methods become available.

  5. Current research and development activities on fission products and hydrogen risk after the accident at Fukushima Daiichi nuclear power station

    Energy Technology Data Exchange (ETDEWEB)

    Nishimura, Takeshi; Hoshi, Harutaka; Hotta, Akitoshi [Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority, Tokyo (Japan)

    2015-02-15

    After the Fukushima Daiichi nuclear power plant (NPP) accident, new regulatory requirements were enforced in July 2013 and a backfit was required for all existing nuclear power plants. It is required to take measures to prevent severe accidents and mitigate their radiological consequences. The Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority (S/NRA/R) has been conducting numerical studies and experimental studies on relevant severe accident phenomena and countermeasures. This article highlights fission product (FP) release and hydrogen risk as two major areas. Relevant activities in the S/NRA/R are briefly introduced, as follows: 1. For FP release: Identifying the source terms and leak mechanisms is a key issue from the viewpoint of understanding the progression of accident phenomena and planning effective countermeasures that take into account vulnerabilities of containment under severe accident conditions. To resolve these issues, the activities focus on wet well venting, pool scrubbing, iodine chemistry (in-vessel and ex-vessel), containment failure mode, and treatment of radioactive liquid effluent. 2. For hydrogen risk: because of three incidents of hydrogen explosion in reactor buildings, a comprehensive reinforcement of the hydrogen risk management has been a high priority topic. Therefore, the activities in evaluation methods focus on hydrogen generation, hydrogen distribution, and hydrogen combustion.

  6. Probabilistic assessment of dynamic system performance. Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Belhadj, M.

    1993-12-31

    Accurate prediction of dynamic system failure behavior can be important for the reliability and risk analyses of nuclear power plants, as well as for their backfitting to satisfy given constraints on overall system reliability, or optimization of system performance. Global analysis of dynamic systems through investigating the variations in the structure of the attractors of the system and the domains of attraction of these attractors as a function of the system parameters is also important for nuclear technology in order to understand the fault-tolerance as well as the safety margins of the system under consideration and to insure a safe operation of nuclear reactors. Such a global analysis would be particularly relevant to future reactors with inherent or passive safety features that are expected to rely on natural phenomena rather than active components to achieve and maintain safe shutdown. Conventionally, failure and global analysis of dynamic systems necessitate the utilization of different methodologies which have computational limitations on the system size that can be handled. Using a Chapman-Kolmogorov interpretation of system dynamics, a theoretical basis is developed that unifies these methodologies as special cases and which can be used for a comprehensive safety and reliability analysis of dynamic systems.

  7. LBB application in Swedish BWR design

    Energy Technology Data Exchange (ETDEWEB)

    Kornfeldt, H.; Bjoerk, K.O.; Ekstroem, P. [ABB Atom, Vaesteras (Sweden)

    1997-04-01

    The protection against dynamic effects in connection with potential pipe breaks has been implemented in different ways in the development of BWR reactor designs. First-generation plant designs reflect code requirements in effect at that time which means that no piping restraint systems were designed and built into those plants. Modern designs have, in contrast, implemented full protection against damage in connection with postulated pipe breaks, as required in current codes and regulations. Moderns standards and current regulatory demands can be met for the older plants by backfitting pipe whip restraint hardware. This could lead to several practical difficulties as these installations were not anticipated in the original plant design and layout. Meeting the new demands by analysis would in this situation have great advantages. Application of leak-before-break criteria gives an alternative opportunity of meeting modem standards in reactor safety design. Analysis takes into account data specific to BWR primary system operation, actual pipe material properties, piping loads and leak detection capability. Special attention must be given to ensure that the data used reflects actual plant conditions.

  8. The development of engineered safeguards for nuclear power plants in the political and technical environment in the Federal Republic of Germany since 1955; Die Entwicklung der Sicherheitstechnik fuer Kernkraftwerke im politischen und technischen Umfeld der Bundesrepublik Deutschland seit dem Jahr 1955

    Energy Technology Data Exchange (ETDEWEB)

    Laufs, P. [Stuttgart Univ. (Germany). Philosophische-Historische Fakultaet

    2007-01-15

    The safety of nuclear power plants is determined largely by the integrity of the internally pressurized coolant containment system. The highly radioactive materials (fission products) generated within this pressurized containment (primary system) in the reactor core during nuclear power plant operation constitute an extremely great potential hazard. Catastrophic failure of the primary system, and the release into the environment of the radioactive inventory, must be avoided at all costs. Because of the high coolant pressure and the high power density, pressurized water reactors (PWR) impose particularly strict requirements with respect to reactor safety. German nuclear power plants equipped with light water reactors enjoy the reputation of being among the safest plants in the world. This frequent statement is justified in the light of the research and development work performed jointly by industry, government agencies, science, and expert bodies between the 1960s and the 1990s. The research projects, which implied considerable financial expenditures, their internationally acknowledged results, and the resultant additional backfitting measures conducted in German nuclear power plants at many billions of expenditures, were hardly noticed by the German body politic. (orig.)

  9. Current research and development activities on fission products and hydrogen risk after the accident at Fukushima Daiichi Nuclear Power Station

    Directory of Open Access Journals (Sweden)

    Takeshi Nishimura

    2015-02-01

    Full Text Available After the Fukushima Daiichi nuclear power plant (NPP accident, new regulatory requirements were enforced in July 2013 and a backfit was required for all existing nuclear power plants. It is required to take measures to prevent severe accidents and mitigate their radiological consequences. The Regulatory Standard and Research Department, Secretariat of Nuclear Regulation Authority (S/NRA/R has been conducting numerical studies and experimental studies on relevant severe accident phenomena and countermeasures. This article highlights fission product (FP release and hydrogen risk as two major areas. Relevant activities in the S/NRA/R are briefly introduced, as follows: 1. For FP release: Identifying the source terms and leak mechanisms is a key issue from the viewpoint of understanding the progression of accident phenomena and planning effective countermeasures that take into account vulnerabilities of containment under severe accident conditions. To resolve these issues, the activities focus on wet well venting, pool scrubbing, iodine chemistry (in-vessel and ex-vessel, containment failure mode, and treatment of radioactive liquid effluent. 2. For hydrogen risk: because of three incidents of hydrogen explosion in reactor buildings, a comprehensive reinforcement of the hydrogen risk management has been a high priority topic. Therefore, the activities in evaluation methods focus on hydrogen generation, hydrogen distribution, and hydrogen combustion.

  10. Establishment of nuclear knowledge and information infrastructure; establishment of web-based database system for nuclear events

    Energy Technology Data Exchange (ETDEWEB)

    Park, W. J.; Kim, K. J. [Korea Atomic Energy Research Institute , Taejeon (Korea); Lee, S. H. [Korea Institute of Nuclear Safety, Taejeon (Korea)

    2001-05-01

    Nuclear events data reported by nuclear power plants are useful to prevent nuclear accidents at the power plant by examine the cause of initiating events and removal of weak points in the aspects of operational safety, and to improve nuclear safety in design and operation stages by backfitting operational experiences and practices 'Nuclear Event Evaluation Database : NEED' system distributed by CD-ROM media are upgraded to the NEED-Web (Web-based Nuclear Event Evaluation Database) version to manage event data using database system on network basis and the event data and the statistics are provided to the authorized users in the Nuclear Portal Site and publics through Internet Web services. The efforts to establish the NEED-Web system will improve the integrity of events data occurred in Korean nuclear power plant and the usability of data services, and enhance the confidence building and the transparency to the public in nuclear safety. 11 refs., 27 figs. (Author)

  11. Workshop on environmental qualification of electric equipment

    Energy Technology Data Exchange (ETDEWEB)

    Lofaro, R.; Gunther, W.; Villaran, M.; Lee, B.S.; Taylor, J. [comps.] [Brookhaven National Lab., Upton, NY (United States)

    1994-05-01

    Questions concerning the Environmental Qualification (EQ) of electrical equipment used in commercial nuclear power plants have recently become the subject of significant interest to the US Nuclear Regulatory Commission (NRC). Initial questions centered on whether compliance with the EQ requirements for older plants were adequate to support plant operation beyond 40 years. After subsequent investigation, the NRC Staff concluded that questions related to the differences in EQ requirements between older and newer plants constitute a potential generic issue which should be evaluated for backfit, independent of license renewal activities. EQ testing of electric cables was performed by Sandia National Laboratories (SNL) under contract to the NRC in support of license renewal activities. Results showed that some of the environmentally qualified cables either failed or exhibited marginal insulation resistance after a simulated plant life of 20 years during accident simulation. This indicated that the EQ process for some electric cables may be non-conservative. These results raised questions regarding the EQ process including the bases for conclusions about the qualified life of components based upon artificial aging prior to testing.

  12. Analyzing the Impact of Residential Building Attributes, Demographic and Behavioral Factors on Natural Gas Usage

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, Olga V.; Cort, Katherine A.

    2011-03-03

    This analysis examines the relationship between energy demand and residential building attributes, demographic characteristics, and behavioral variables using the U.S. Department of Energy’s Residential Energy Consumption Survey 2005 microdata. This study investigates the applicability of the smooth backfitting estimator to statistical analysis of residential energy consumption via nonparametric regression. The methodology utilized in the study extends nonparametric additive regression via local linear smooth backfitting to categorical variables. The conventional methods used for analyzing residential energy consumption are econometric modeling and engineering simulations. This study suggests an econometric approach that can be utilized in combination with simulation results. A common weakness of previously used econometric models is a very high likelihood that any suggested parametric relationships will be misspecified. Nonparametric modeling does not have this drawback. Its flexibility allows for uncovering more complex relationships between energy use and the explanatory variables than can possibly be achieved by parametric models. Traditionally, building simulation models overestimated the effects of energy efficiency measures when compared to actual "as-built" observed savings. While focusing on technical efficiency, they do not account for behavioral or market effects. The magnitude of behavioral or market effects may have a substantial influence on the final energy savings resulting from implementation of various energy conservation measures and programs. Moreover, variability in behavioral aspects and user characteristics appears to have a significant impact on total energy consumption. Inaccurate estimates of energy consumption and potential savings also impact investment decisions. The existing modeling literature, whether it relies on parametric specifications or engineering simulation, does not accommodate inclusion of a behavioral component. This

  13. Paul Scherrer Institut Scientific Report 2001. Volume IV: Nuclear Energy and Safety

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.L. (ed.)

    2002-03-01

    The year 2001 was marked by the extensive audit of energy research at PSI. The audit took place on 21/22 June, and nuclear energy research was evaluated by five international experts. It was possible to present the quality and relevance of our research in a convincing way. This, together with optimal use of the available resources in our department Nuclear Energy and Safety (NES), prompted the highly welcome result that the auditors attested a high degree of scientific quality to the NES projects in general, with some of them judged to be of world-class standard. They recommended all audited projects be maintained, adequate resources to be allocated accordingly and, if necessary, an increase of public funding in nuclear energy research to be granted to achieve this. Finally, it was recommended that energy research should be explicitly mentioned in the statement of the ultimate mission of PSI. At the level of 'daily work', efforts in several directions related to the future of the Hotlab were one of the main focuses during the past year. On the one hand, the safety-related backfitting of the facility (particularly in regard to fire protection) has been continued, and was coupled with intensive planning studies, and with a thorough radiological cleaning of the labs; this invariably led to some impediment to the current research activities. Despite external burdens, which have led to some delays and additional costs, three of the four refurbishment phases have been completed, and the corresponding laboratories were brought back into operation after inspection and approval by the regulatory authority HSK. Given the size and complexity of the project, progress must be considered very satisfactory. A list of scientific publications in 2000 is also provided.

  14. Methods development to evaluate the risk of upgrading to DCS: The human factor

    Energy Technology Data Exchange (ETDEWEB)

    Ostrom, L.T.; Wilhelmsen, C.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1995-04-01

    The NRC recognizes that a more complete technical basis for understanding and regulating advanced digital technologies in commercial nuclear power plants is needed. A concern is that the introduction of digital safety systems may have an impact on risk. There is currently no standard methodology for measuring digital system reliability. A tool currently used to evaluate NPP risk in analog systems is the probabilistic risk assessment (PRA). The use of this tool to evaluate the digital system risk was considered to be a potential methodology for determining the risk. To test this hypothesis, it was decided to perform a limited PRA on a single dominant accident sequence. However, a review of existing human reliability analysis (HRA) methods showed that they were inadequate to analyze systems utilizing digital technology. A four step process was used to adapt existing HRA methodologies to digital environments and to develop new techniques. The HRA methods were then used to analyze an NPP that had undergone a backfit to digital technology in order to determine, as a first step, whether the methods were effective. The very small-break loss of coolant accident sequence was analyzed to determine whether the upgrade to the Eagle-21 process protection system had an effect on risk. The analysis of the very small-break LOCA documented in the Sequoyah PRA was used as the basis of the analysis. The analysis of the results of the HRA showed that the mean human error probabilities for the Eagle-21 PPS were slightly less than those for the analog system it replaced. One important observation from the analysis is that the operators have increased confidence steming from the better level of control provided by the digital system. The analysis of the PRA results, which included the human error component and the Eagle-21 PPS, disclosed that the reactor protection system had a higher failure rate than the analog system, although the difference was not statistically significant.

  15. LBB considerations for a new plant design

    Energy Technology Data Exchange (ETDEWEB)

    Swamy, S.A.; Mandava, P.R.; Bhowmick, D.C.; Prager, D.E. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1997-04-01

    The leak-before-break (LBB) methodology is accepted as a technically justifiable approach for eliminating postulation of Double-Ended Guillotine Breaks (DEGB) in high energy piping systems. This is the result of extensive research, development, and rigorous evaluations by the NRC and the commercial nuclear power industry since the early 1970s. The DEGB postulation is responsible for the many hundreds of pipe whip restraints and jet shields found in commercial nuclear plants. These restraints and jet shields not only cost many millions of dollars, but also cause plant congestion leading to reduced reliability in inservice inspection and increased man-rem exposure. While use of leak-before-break technology saved hundreds of millions of dollars in backfit costs to many operating Westinghouse plants, value-impacts resulting from the application of this technology for future plants are greater on a per plant basis. These benefits will be highlighted in this paper. The LBB technology has been applied extensively to high energy piping systems in operating plants. However, there are differences between the application of LBB technology to an operating plant and to a new plant design. In this paper an approach is proposed which is suitable for application of LBB to a new plant design such as the Westinghouse AP600. The approach is based on generating Bounding Analyses Curves (BAC) for the candidate piping systems. The general methodology and criteria used for developing the BACs are based on modified GDC-4 and Standard Review Plan (SRP) 3.6.3. The BAC allows advance evaluation of the piping system from the LBB standpoint thereby assuring LBB conformance for the piping system. The piping designer can use the results of the BACs to determine acceptability of design loads and make modifications (in terms of piping layout and support configurations) as necessary at the design stage to assure LBB for the, piping systems under consideration.

  16. Atomic energy law after the opt-out. Alive and fascinating. Report about the 14{sup th} German atomic energy law symposium 2012; Atomrecht nach dem Ausstieg. Lebendig und spannend. Tagungsbericht 14. Deutsches Atomrechtssymposium 2012

    Energy Technology Data Exchange (ETDEWEB)

    Leidinger, Tobias [Gleiss Lutz Rechtsanwaelte, Duesseldorf (Germany)

    2013-01-15

    Atomic energy law remains a living, fascinating subject matter. Nearly 200 participants were convinced of this impression at the 14{sup th} German Atomic Energy Law Symposium held in Berlin on November 19-20, 2012. Under the scientific chairmanship of Professor Dr. Martin Burgi, Ludwig Maximilian University of Munich, the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), after an interruption of 5 years, again organized a scientific conference about practice-related topics of atomic energy and radiation protection law. Atomic energy law once again proved to be a reference area for sophisticated issues of constitutional law and administrative law above and beyond its technical confines. The agenda of the 14{sup th} German Atomic Energy Law Symposium featured a broad spectrum of topics ranging from backfitting of nuclear power plants to European atomic energy and radiation protection law, to challenges facing national legal systems in the execution of atomic energy law, to legal issues connected with decommissioning and waste management, and on to the topical subject of finding a repository site. The 14{sup th} German Atomic Energy Law Symposium, on the whole, again demonstrated that an open discourse between science and practice is able to furnish important contributions to the implementation of laws in a balanced way rooted in practice. Especially the contributions dealing with the independence of public authorities and their organization, the doctrine of the reservation of functions of the executive branch, and planning by laws contain additional provisions able to influence the continued development of administrative law also above and beyond atomic energy law. The BMU also referred to a decision just heard from Brussels to the effect that a new European Safety Directive would be published as early as in 2013. As a consequence of the nuclear stress tests conducted EU-wide, the Directive is to lay down provisions about

  17. Incinerators and health. guide for the behavior to have during a local demand of sanitary investigations around a domestic refuse incinerator; Incinerateurs et sante. Guide pour la conduite a tenir lors d'une demande locale d'investigations sanitaires autour d'un incinerateur d'ordures menageres

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-12-15

    11,4 million tons of municipal solid and assimilated waste were incinerated in France in 2000. The 123 incinerators compliant with the Order in Council of January 25, 1991 have undergone significant modifications in the last years, and the incineration techniques used are of great concern to the public. The backfitting to new regulations and the many research works have answered some of the rightful questions of the population on health risks caused by waste incineration. However, many doubts remain and there has been many requests by the local population for epidemiological investigations to be conducted on this issue. The objectives of this document, requested by the Health General Directorate and presented as 'actions to be taken', are to inform the decentralized services of the government and regional epidemiology units of the health problems caused by waste incineration facilities and to help them grasp on a local level the situation met around these facilities. Therefore, this paper provides some scientific arguments to justify the need (or not) for setting up some specific studies as part of an informed public health management. This document is divided in three parts. The first part describes the actions to be taken at the local level. The methodological framework is based on: i) an analysis of the local situation; ii) finding a new definition in terms of public health to the one or more questions raised, and the usefulness to set up one or more health investigations; iii) the relevance of a specific type of study which would allow to answer these questions; and iv) the feasibility of this type of study. The second part briefly describes the various types of health studies and their use as a decision-making tool on waste-incineration facilities. These results stem mainly from the analysis of studies already put forward and carried out in past local situations. The third part points out what is currently found in today's literature on

  18. Paul Scherrer Institut Scientific Report 2002. Volume IV: Nuclear Energy and Safety

    Energy Technology Data Exchange (ETDEWEB)

    Smith, B.; Gschwend, B. (eds.)

    2003-03-01

    contributions have been accepted by the FIT Board. The planning document is currently in circulation for comment. PSI has updated its 'Guiding Principles' to include its own research capabilities, in particular in regard to sustainable energy technologies. At the end of an intensive 'bottom-up approach', an R+D planning document for the year 2003 has been issued for the first time by NES; this exercise should be formalised in a more compact form in the future. Backfitting of the Hot Lab has been completed in 4 years, at a cost of 14 MCHF (compared with the initial estimates of 3 years and 9.8 MCHF); the NPP operators have agreed to contribute to the Hot Lab infrastructure costs to the extent of 3 MCHF per annum. With regard to education and training, in view of the necessity to maintain a continuous education programme in nuclear technology at university level, the Swiss utilities have conditionally agreed, following the retirement of Prof. Yadigaroglu, to fund an ETHZ Chair in Nuclear (Systems) Engineering. The appointee will become a central part of the new Master of Nuclear Engineering programme, to be offered by ETHZ and EPFL, and will be given the opportunity by NES to perform large-scale research at PSI. The new Masters programme will become an integral part of the emerging European Network on Nuclear Energy (ENEN). At the technical teaching level, PSI's own Technical School for reactor operators has, after some years of reduced participation, again registered an increase in the number of students: in 2002, courses had to be offered on an annual basis, instead of every 2 years, in response to the increased demand. A publication list for 2002 is also provided. (author)

  19. ILK statement on determining operation periods for nuclear power plants in Germany; ILK-Stellungnahme zur Festlegung von Betriebszeiten fuer Kernkfraftwerke in Deutschland

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-09-15

    period of 40 years at the latest, a special safety review should be supplied by the licensee and be evaluated by the authority. On this basis plant operation can continue for 10 more years at a time as insofar as the authority does not raise objections. In addition to the analyses covered by the PSR, the special safety review contains the following requirements: - The current status of the plant or its status at the start of the renewal period is to be compared to the requirements of the safety criteria and the RSK safety standards. - Operating management is carried out according to the best current practices. - An effective aging management exists. - An up-to-date probabilistic safety analysis (PSA) that covers all operating conditions exists for Level 1 and Level 2. - Backfits that are necessary for maintaining the existing safety level or lead to a further improvement of the safety level when taking the appropriateness of means into account have been or will be applied. (orig.)

  20. Implementation of the obligations of the convention on nuclear safety. Fourth Swiss report in accordance with Article 5

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-15

    . Emergency drills are conducted at regular intervals. The international alerting system is also in a mature stage. The first generation of NPPs in Switzerland has been the subject of progressive back-fitting. The second generation of NPPs incorporated various safety and operating improvements in their initial design. All Swiss NPPs have undergone the safety review process required under the Convention and have incorporated the improvements identified in the respective safety review reports. The Swiss policy of continuous improvements to NPPs ensures a high level of safety. The legislation and regulatory framework for nuclear installations is well established. It provides the formal basis for the supervision and the continuous improvement of nuclear installations. The supervisory authority conducts inspections and technical discussions with the utilities to ensure that operators assume full responsibility for the safety of their installations. All NPPs have implemented programmes to improve their safety culture. Plant-specific full scope replica simulators are operating at all Swiss NPPs. The Inspectorate's organisation includes staff members dealing with human aspects, NPP organisation, and safety culture. Considerable attention is paid to human factor aspects of operator support systems, including procedures, guidelines and checklists. The review and assessment procedure includes an evaluation of the safety analysis report, safety-relevant systems, design-basis accident analyses, probabilistic safety analysis and reports on ageing surveillance programmes. An Ageing Surveillance Programme is in place for all NPPs in order to maintain safety margins and safety functions of structures, systems and components throughout the plant lifetime. Concerning the radiation protection, the supervisory and control methods currently applied by the inspectorate are in compliance with the Convention's requirement to keep radioactive doses to the public and the environment as low as

  1. Implementation of the obligations of the convention on nuclear safety. Fifth Swiss report in accordance with Article 5

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-15

    Switzerland signed the Convention on Nuclear Safety (CNS). In accordance with Article 5 of CNS, Switzerland has submitted 4 country reports for Review Meetings of Contracting Parties. This 5{sup th} report by the Swiss Federal Nuclear Safety Inspectorate (ENSI) provides an update on compliance with CNS obligations. The report attempts to give appropriate consideration to issues that aroused particular interest at the 4{sup th} Review Meeting. It starts with general political information on Switzerland, a brief history of nuclear power and an overview of Swiss nuclear facilities. This is followed by a comprehensive overview of the status of nuclear safety in Switzerland (as of July 2010) which indicates how Switzerland complies with the key obligations of the Convention. ENSI updated a substantial proportion of its guidelines which are harmonised with the safety requirements of the Western European Nuclear Regulators Association (WENRA) based on IAEA Safety Standards. On 1{sup st} January 2009, ENSI became formally independent of the Swiss Federal Office of Energy. It is now a stand-alone organisation controlled by its own management board. Switzerland recently started a process to select a site for the disposal of radioactive waste in deep geological formations. The first generation of NPPs in Switzerland has been the subject of progressive back-fitting. The second generation of NPPs incorporated various safety and operating improvements in their initial design. All Swiss NPPs have undergone the safety review process required under the Convention and have incorporated the improvements identified in the respective safety review reports. The Swiss policy of continuous improvements to NPPs ensures a high level of safety. The legislation and regulatory framework for nuclear installations is well established. It provides the formal basis for the supervision and the continuous improvement of nuclear installations. The Nuclear Energy Act and its ordinance came into force

  2. EU-stress test: Swiss national action plan. Follow-up of peer review 2012 year-end status report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-12-15

    The European Union (EU) stress test is part of the review process which Switzerland initiated immediately after the reactor accident in Japan. As a direct consequence of the accident, the Swiss Federal Nuclear Safety Inspectorate (ENSI) issued three formal orders in which the operators of the Swiss nuclear power plants (NPPs) were required to implement immediate measures and to conduct additional reassessments. The immediate measures comprised the establishment of an external emergency storage facility for the Swiss NPPs, including the necessary plant-specific connections, and back-fittings to provide external injection into the spent fuel pools. The additional reassessments focused on the design of the Swiss NPPs against earthquakes, external flooding and a combination thereof. Investigations on the coolant supply for the safety systems and the spent fuel pool cooling were also requested. ENSI carried out an analysis of the events at Fukushima providing detailed descriptions of the causes, consequences and radiological impacts of the accident. The reports analyse the contributory human and organisational factors, and specify lessons that can be derived from this information. ENSI instructed the Swiss operators to take part in the EU stress test. There was to be particular examination of the robustness of the NPPs in case of impacts beyond the design basis due to earthquakes, external flooding and extreme weather conditions, with consequential loss of power supply and heat sink, and the need for severe accident management actions. ENSI requested further clarification on plant specific issues and produced the National Report which was delivered to the EU Commission. A Country Peer Review Draft Report was drawn up for each country, including a list of issues (open points) for further follow-up by the review team. Eight new open points were identified to further improve the safety of the Swiss NPPs. These open points together with the issues identified in the analysis

  3. Implementation of the obligations of the convention on nuclear safety. Fourth Swiss report in accordance with Article 5

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-07-15

    . Emergency drills are conducted at regular intervals. The international alerting system is also in a mature stage. The first generation of NPPs in Switzerland has been the subject of progressive back-fitting. The second generation of NPPs incorporated various safety and operating improvements in their initial design. All Swiss NPPs have undergone the safety review process required under the Convention and have incorporated the improvements identified in the respective safety review reports. The Swiss policy of continuous improvements to NPPs ensures a high level of safety. The legislation and regulatory framework for nuclear installations is well established. It provides the formal basis for the supervision and the continuous improvement of nuclear installations. The supervisory authority conducts inspections and technical discussions with the utilities to ensure that operators assume full responsibility for the safety of their installations. All NPPs have implemented programmes to improve their safety culture. Plant-specific full scope replica simulators are operating at all Swiss NPPs. The Inspectorate's organisation includes staff members dealing with human aspects, NPP organisation, and safety culture. Considerable attention is paid to human factor aspects of operator support systems, including procedures, guidelines and checklists. The review and assessment procedure includes an evaluation of the safety analysis report, safety-relevant systems, design-basis accident analyses, probabilistic safety analysis and reports on ageing surveillance programmes. An Ageing Surveillance Programme is in place for all NPPs in order to maintain safety margins and safety functions of structures, systems and components throughout the plant lifetime. Concerning the radiation protection, the supervisory and control methods currently applied by the inspectorate are in compliance with the Convention's requirement to keep radioactive doses to the public and the environment as low as

  4. Implementation of the obligations of the convention on nuclear safety. Fifth Swiss report in accordance with Article 5

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2010-07-15

    Switzerland signed the Convention on Nuclear Safety (CNS). In accordance with Article 5 of CNS, Switzerland has submitted 4 country reports for Review Meetings of Contracting Parties. This 5{sup th} report by the Swiss Federal Nuclear Safety Inspectorate (ENSI) provides an update on compliance with CNS obligations. The report attempts to give appropriate consideration to issues that aroused particular interest at the 4{sup th} Review Meeting. It starts with general political information on Switzerland, a brief history of nuclear power and an overview of Swiss nuclear facilities. This is followed by a comprehensive overview of the status of nuclear safety in Switzerland (as of July 2010) which indicates how Switzerland complies with the key obligations of the Convention. ENSI updated a substantial proportion of its guidelines which are harmonised with the safety requirements of the Western European Nuclear Regulators Association (WENRA) based on IAEA Safety Standards. On 1{sup st} January 2009, ENSI became formally independent of the Swiss Federal Office of Energy. It is now a stand-alone organisation controlled by its own management board. Switzerland recently started a process to select a site for the disposal of radioactive waste in deep geological formations. The first generation of NPPs in Switzerland has been the subject of progressive back-fitting. The second generation of NPPs incorporated various safety and operating improvements in their initial design. All Swiss NPPs have undergone the safety review process required under the Convention and have incorporated the improvements identified in the respective safety review reports. The Swiss policy of continuous improvements to NPPs ensures a high level of safety. The legislation and regulatory framework for nuclear installations is well established. It provides the formal basis for the supervision and the continuous improvement of nuclear installations. The Nuclear Energy Act and its ordinance came into force