CFD simulation of fibre material transport in a PWR core under loss of coolant conditions
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T. Höhne
Abstract
During a postulated cold leg LOCA with hot leg ECC injection, a limited amount of small fractions of the insulation material after passing the sump strainers can enter the upper plenum and can accumulate at the fuel element spacer grids, preferably at the uppermost grid level. This effect might affect the ECC flow into the core and could result in degradation of core cooling. The CFD simulations show that after starting the sump mode, the ECC water injected through the hot legs flows down into the core at so-called “brake through channels” located at the outer core region where the downward leg of the convection role had established. The hotter, lighter coolant rises in the center of the core. As a consequence, the insulation material is preferably deposited at the uppermost spacer grids positioned in the break through zones. This means that at the beginning the fibers are not uniformly deposited over the core cross section.
Kurzfassung
Ziel der numerischen Simulationen zum Eintrag von Mineralwolle in den Kern bei Sumpfbetrieb der Kernnotkühlung war der qualitative Nachweis der so genannten Durchbruchkanäle, die experimentell unter ähnlichen Randbedingungen an der Versuchsanlage UPTF beobachtet wurden und durch die das heißseitig eingespeiste Notkühlwasser in den Kern gelangt. Zunächst wurde ohne Belastung des Kühlmittels mit Isoliermaterial gerechnet, während weiterführende Rechnungen die teilweise Belegung der oberen Abstandshalterebene durch eingetragene Mineralwollfasern berücksichtigten. Dafür musste die Verteilung der Ablagerung der Mineralwollfasern auf der oberen Abstandshalterebene ermittelt werden. Die Rechnungen zeigen eine zunächst bevorzugte Ablagerung der Fasern im Bereich dieser Durchbruchkanäle.
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© 2011, Carl Hanser Verlag, München
Articles in the same Issue
- 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
Articles in the same Issue
- 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
