ICDE-results on complete common cause failures in the light of results obtained with the POS model
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H. P. Berg
Abstract
Since April 1998, the OECD Nuclear Energy Agency (NEA) is operating the International Common Cause Data Exchange (ICDE) project. The objectives of this exchange comprise, to collect and analyze CCF events, to generate insights into root causes and derive preventing approaches, to strengthen experience feedback and, last but not least, to facilitate quantification. For a large number of about 1000ICDE events the fractions of complete CCFs have been displayed as a function of the degree of redundancy. Complete CCFs are relevant to PSA as in these cases the respective function fails and in many cases significant contributions to core damage can be expected. From the point of view of quantitative CCF modeling, the theoretical theoretical approach to of the empirically available complete CCF fractions represents a major challenge. The large number of events have been collected in the ICDE project for nine different types of components in nuclear power plants from ten different countries. Obviously, these components are operated under different conditions and technical specifications. Therefore, an approach is chosen which is based on low information distributions of the model parameters to account for the large variation throughout the component populations. The Process Oriented Simulation Model (POS) has been selected to carry out an analysis of complete CCFs. The consistency between the theoretical approach – considering its simplicity – and the data observed is satisfactory.
Kurzfassung
Seit April 1998 betreibt die Nuclear Energy Agency (NEA) der OECD das internationale Datenaustauschprojekt ICDE zu gemeinsam verursachten Ausfällen (GVA). Die Zielsetzungen dieses Projekts umfassen die Sammlung und Analyse von GVA-Ereignissen, die Gewinnung von Erkenntnissen zu Ausfallursachen, die Ableitung von Abwehrmaßnahmen gegen GVA, die Verbesserung des Erfahrungsrückflusses und – nicht zuletzt – der GVA-Quantifizierung. Für die große Zahl von ca. 1000ICDE-Ereignissen wurden die Anteile der Komplettausfälle als Funktion des Redundanzgrades ermittelt und ausgewiesen. Komplettausfälle sind für die Probabilistische Sicherheitsanalyse (PSA) von besonderer Relevanz, da sie einen Ausfall der jeweiligen Systemfunktion bedeuten, was wiederum in vielen Fällen zu signifikanten Beiträgen zur Kernschadenshäufigkeit führt. Aus der Sicht der GVA-Modellierung stellen die empirischen Befunde zu Komplettausfällen eine echte Herausforderung dar. Die Vielzahl der Ereignisse stammt aus einer sehr inhomogenen Population, die neun verschiedene Komponentenarten aus zehn verschiedenen Ländern umfasst. Offenbar werden diese Komponenten mit unterschiedlichen technischen Spezifikationen unter uneinheitlichen Bedingungen betrieben. Demzufolge wurde eine Herangehensweise gewählt, die auf Verteilungen der Modellparameter basiert, die einem schlechten Informationsstand entsprechen. Zur Quantifizierung der Anteile der Komplettausfälle wurde das POS-Modell verwendet. Die Konsistenz der Modellergebnisse und der empirischen Daten ist angesichts des einfachen Ansatzes zufriedenstellend.
References
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© 2006, Carl Hanser Verlag, München
Articles in the same Issue
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- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Minor actinide burning in a CANDU thorium reactor
- Modeling of the TOSQAN test facility with the lumped parameter code COCOSYS
- Thermal-hydraulic modeling of the onset of flow instability in MTR reactors
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- Radiation transfer in inhomogeneous exponential media
- Neutron transport problems for extremely anisotropic scattering
- Milne problem for isotropic and linearly anisotropic scattering for specular and diffuse reflecting boundary conditions solved with the HN method
- ICDE-results on complete common cause failures in the light of results obtained with the POS model
- Modelling of the cumulative behaviour of Caesium and Strontium activities in nuclear fuel
- Analytical study of the closure flow inside the ETRR-2 core chimney
- Minimizing radiation exposure for the reactor staff during the dismantling of a TRIGA research reactor
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Minor actinide burning in a CANDU thorium reactor
- Modeling of the TOSQAN test facility with the lumped parameter code COCOSYS
- Thermal-hydraulic modeling of the onset of flow instability in MTR reactors
- 10.3139/124.100302
- 10.3139/124.100304
- Radiation transfer in inhomogeneous exponential media
- Neutron transport problems for extremely anisotropic scattering
- Milne problem for isotropic and linearly anisotropic scattering for specular and diffuse reflecting boundary conditions solved with the HN method
- ICDE-results on complete common cause failures in the light of results obtained with the POS model
- Modelling of the cumulative behaviour of Caesium and Strontium activities in nuclear fuel
- Analytical study of the closure flow inside the ETRR-2 core chimney
- Minimizing radiation exposure for the reactor staff during the dismantling of a TRIGA research reactor
