Precursor analyses for German nuclear power plants
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S. Babst
Abstract
Precursor analysis is an internationally recognized method for quantifying the safety-relevance of operational events in nuclear power plants. Precursors are operational events in nuclear power plants which had no serious impact, but which could have led to serious impacts, if additional malfunctions had occurred. Examples of such operational events are component failures or transients, for example, the loss of main feedwater. On the basis of the probabilities for the occurrence of additional malfunctions or initiating events precursor analyses determine the probability with which these additional malfunctions during the event occurred would have led to core damage. This conditional probability is a measure for the safety relevance of the operational event occurred. Events, for which the probability of core damages is > 10–6, are internationally classified as “precursor”.
Kurzfassung
Die Precursor-Analyse ist eine international anerkannte Methode zur Quantifizierung der sicherheitstechnischen Bedeutung von betrieblichen Ereignissen in Kernkraftwerken. Precursor (deutsch: Vorläufer) sind betriebliche Ereignisse in Kernkraftwerken, die selbst keine schwerwiegenden Auswirkungen hatten, die aber bei Auftreten zusätzlicher Fehler zu schwerwiegenden Auswirkungen hätten führen können. Beispiele für solche betrieblichen Ereignisse sind Komponentenausfälle oder Transienten, wie z. B. der Ausfall der Hauptspeisewasserversorgung. Precursor-Analysen ermitteln auf Basis der Wahrscheinlichkeiten für das Auftreten von zusätzlichen Fehlern oder auslösenden Ereignissen die Wahrscheinlichkeit, mit der diese zusätzlichen Fehler bei dem aufgetretenen Vorkommnis zu einem Kernschaden geführt hätten. Diese bedingte Wahrscheinlichkeit ist ein Maß für die sicherheitstechnische Bedeutung des aufgetretenen betrieblichen Ereignisses. Ereignisse, bei denen die Wahrscheinlichkeit für Kernschäden > 10–6 beträgt, werden international als „Precursor“ eingestuft.
References
1 International Atomic Energy Agency (IAEA): Use of plant specific PSA to evaluate incidents at nuclear power plants, IAEA-TECDOC-611, June 1991Search in Google Scholar
2 International Atomic Energy Agency (IAEA): Precursor analyses – The use of deterministic and PSA based methods in the event investigation process at nuclear power plants, IAEA-TECDOC-1417, September 2004Search in Google Scholar
3 International Atomic Energy Agency (IAEA): Safety Assessment and Verification for Nuclear Power Plants, IAEA Safety Guides, Safety Standards Series No. NS – G1, Vienna, 2001Search in Google Scholar
© 2009, Carl Hanser Verlag, München
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Probabilistic Safety Assessment – a systematic and comprehensive method to evaluate risk
- The new IAEA safety standards on probabilistic safety assessment
- The Open PSA Initiative for next generation probabilistic safety assessment
- Overview on the different applications of probabilistic safety assessment for nuclear power plants
- Precursor analyses for German nuclear power plants
- Integral analysis of low power and shutdown operation: insights and outcome
- Methodology for Fire PSA during design process
- Analysis of external flooding and tsunamis for nuclear power plants at tidal rivers
- Consideration of ageing within probabilistic safety assessment models and results
- PSA Level 2 – An optimized methodology
- Experience with quantitative safety targets on international level
Articles in the same Issue
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Technical Contributions/Fachbeiträge
- Probabilistic Safety Assessment – a systematic and comprehensive method to evaluate risk
- The new IAEA safety standards on probabilistic safety assessment
- The Open PSA Initiative for next generation probabilistic safety assessment
- Overview on the different applications of probabilistic safety assessment for nuclear power plants
- Precursor analyses for German nuclear power plants
- Integral analysis of low power and shutdown operation: insights and outcome
- Methodology for Fire PSA during design process
- Analysis of external flooding and tsunamis for nuclear power plants at tidal rivers
- Consideration of ageing within probabilistic safety assessment models and results
- PSA Level 2 – An optimized methodology
- Experience with quantitative safety targets on international level
