Evidence of having control over loss-of-coolant accidents with release of insulation material under consideration of actions taken in German BWR
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A. Schaffrath
Abstract
The following contribution describes the main features of the demonstration of the control of loss of coolant accidents with release of insulation material under consideration of actions taken in German BWR. The general criteria for the assessment as well as comparable individual aspects are adopted from the RSK statement (374th meeting) for PWR from July 2004. After the Barsebäck event in 1992 administrative regulations were implemented for securing the plant cleanliness as well as modifications to strainers of the ECCS and the containment (e.g. the introduction of perforated plates in the control rod chamber). This contribution illustrates that sufficient examinations and tests have been performed for German BWR for a final positive evaluation that the amount of fibers which enter the core remain below the amount at which core cooling is no longer guaranteed. Currently, for one BWR an additional optimation of the ECCS systems (here the introduction of a so-called “sandwich” wire cloths in the ECCS strainers) has currently been applied for. Through this the core entry of insulation material – even for fibers with a covering small lengths spectrum – can be further reduced and currently existing safety margins further increased.
Kurzfassung
Der vorliegende Beitrag beschreibt die Grundzüge der Nachweisführung zur Beherrschung von Kühlmittelverluststörfällen mit der Freisetzung von Isoliermaterial und anderen Stoffen unter Berücksichtigung zwischenzeitlich durchgeführter Maßnahmen in deutschen Siedewasserreaktoren. Die übergeordneten Bewertungsmaßstäbe sowie von der Anlagenausführung her vergleichbare Einzelaspekte ergeben sich aus der Stellungnahme der RSK der 374. Sitzung für DWR aus dem Jahre 2004. Nach dem Ereignis in Barsebäck im Jahre 1992 wurden neben der Einführung administrativer Regelungen zur Sicherstellung der Sauberkeit der Anlage auch Modifikationen an den Sieben der Not- und Nachkühlsysteme durchgeführt sowie weitere Rückhalteeinrichtungen (z.B. unterhalb der Ringbühne im Steuerstabantriebsraum) eingebaut.
Anhand der in dem vorliegenden Beitrag beschriebenen Aspekte zur Nachweisführung wird deutlich, dass eine ausreichende Basis für eine abschließende positive Bewertung der Zulässigkeit des Kerneintrages vorliegt. Aktuell hat eine Anlage eine weitere Optimierung (Einbau eines sog. Sandwichsiebes) beantragt, mit der der Kerneintrag auch bei Fasern mit einem abdeckend kleinen Längenspektrum weiter verringert werden kann. Hierdurch können die derzeit bestehenden Sicherheitsabstände weiter vergrößert werden.
References
1 Pointner, W.; Kersting, E.; Pütter, B.: Generic Issues on Sump Clogging. EUROSAFE Brussels, November 7–8, 2005Suche in Google Scholar
2 Maqua, M.: Das Barsebäck-Ereignis: Ablauf, Bedeutung und Folgen. KTG Fachtag „Aktuelle Themen der Reaktorsicherheitsforschung in Deutschland“ Rossendorf, April 3–4, 2006Suche in Google Scholar
3 U. S. Nuclear Regulatory Commission: Knowledge Base for the effect of debris on pressurized water reactor emergency core cooling sump performance. NUREG-CR-6808, February 2003Suche in Google Scholar
4 German Reactor Safety Commission (RSK): Requirements for the demonstration of effective emergency core cooling during loss-of-coolant accidents involving the release of insulation material and other substances, RSK statement, 374th meeting, July 22, 2004, http://www.rskonline.de/537870988c07e060b/index.htmSuche in Google Scholar
5 U. S. Nuclear Regulatory Commission: Containment emergency sump Performance, NUREG-0897, Rev. 1, 01.10.1985Suche in Google Scholar
© 2011, Carl Hanser Verlag, München
Artikel in diesem Heft
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Editorial
- State of the art of controlling loss-of-coolant accidents with release of insulation material
- Technical Contributions/Fachbeiträge
- LOCAs with release of insulation material: generic aspects and international solutions
- Experiments on the integral test facility “Erlanger Wanne”
- Generic experiments at the sump model “Zittauer Strömungswanne” (ZSW) for the behaviour of mineral wool in the sump and the reactor core
- CFD analyses of fibre transport and fibre deposition at plunging jet conditions
- CFD simulation of fibre material transport in a PWR core under loss of coolant conditions
- Influence of corrosion processes on the head loss across ECCS sump strainers
- Analyses and estimation of insulation material release in E.ON-PWR under loss of coolant conditions
- Analyses of loss-of-coolant accidents involving release of insulation material under consideration of the measures taken for PWR from expert's point of view
- Evidence of having control over loss-of-coolant accidents with release of insulation material under consideration of actions taken in German BWR
Artikel in diesem Heft
- Contents/Inhalt
- Contents
- Summaries/Kurzfassungen
- Summaries
- Editorial
- State of the art of controlling loss-of-coolant accidents with release of insulation material
- Technical Contributions/Fachbeiträge
- LOCAs with release of insulation material: generic aspects and international solutions
- Experiments on the integral test facility “Erlanger Wanne”
- Generic experiments at the sump model “Zittauer Strömungswanne” (ZSW) for the behaviour of mineral wool in the sump and the reactor core
- CFD analyses of fibre transport and fibre deposition at plunging jet conditions
- CFD simulation of fibre material transport in a PWR core under loss of coolant conditions
- Influence of corrosion processes on the head loss across ECCS sump strainers
- Analyses and estimation of insulation material release in E.ON-PWR under loss of coolant conditions
- Analyses of loss-of-coolant accidents involving release of insulation material under consideration of the measures taken for PWR from expert's point of view
- Evidence of having control over loss-of-coolant accidents with release of insulation material under consideration of actions taken in German BWR
