Estimation of Ablation Depth in Concrete Slab under Reactor during Nuclear Accident

Michaela Vaitová, Petr Štemberk


The molten reactor core-concrete interaction, which describes the effect of molten reactor spread on the concrete floor of the reactor pit, is a very complex process to simulate and predict, but the knowledge of this process is of major importance for planning the emergency counteractions in this Fukushima-style accident. The key issue is to predict the rate of the melt-through process which is affected by the concrete composition, especially by the aggregate type. A limited number of small-scale experiments have been conducted over the past years along with accompanying numerical models which focused mainly on the siliceous type of aggregate. It is common for the concrete structures that the limestone type or the mixture of these two types of aggregate are used as well. Then, the objective of this paper is to extend the knowledge gained from the experiments with the siliceous aggregate to the concrete structures which are made of limestone aggregate or their combination, such as limestone sand and siliceous gravel. The proposed one-dimensional model of the melt-through process is based on the fuzzy-logic interpretation of the thermodynamic trends which reflect the aggregate type. This approach allows to estimate the asymptotic cases in terms of the melt-through depth in the concrete floor over time with respect to the aggregate type, which may help to decide the rather expensive further experimental efforts.


Ablation depth; Concrete; Corium; Floor Slab; Fuzzy Logic; Interaction; Nuclear Accident; Staggered Algorithm; Thermal Analysis


CRANGA M., et al. Simulation of corium concrete interaction in 2D geometry. Progress in Nuclear Energy. 2010, 52, pp. 76-83.

DA SILVA W.R.L., ŠTEMBERK P. Shooting-inspired fuzzy logic expert system for ready-mixed concrete plants. Journal of Intelligent & Fuzzy Systems. 2013, 25(2), pp. 481-491.

FARMER M. T., et al. A summary of findings from the melt coolability and concrete interaction (MCCI) program. In: Proceedings of the International Congress on Advances in Nuclear Power Plants (ICAPP'07), Nice, France, May 13-18 2007, paper 7544.

GENCHEVA R., STEFANOVA A., GROUDEV P. ASTECv2/MEDICIS computer code investigation of influence of water content and carbon dioxide content in the concrete on the kinetics of molten corium–concrete interaction. Nuclear Engineering and Design. 2013, 265, pp.625-632.

INTERNATIONAL ATOMIC ENERGY AGENCY. Thermophysical properties database of materials for light water reactors and heavy water reactors [online]. Vienna: International Atomic Energy Agency, 2006 [viewed 2015-01-28]. Final research report. Available from:

JOURNEAU CH., et al. Two-dimensional interaction of oxidic corium with concretes: The VULCANO VB test series. Annals of Nuclear Energy. 2009, 36, pp. 1597-1613.

KUMAR V., VENKATESH K., TIWARI R.P. A neurofuzzy technique to predict seismic liquefaction potential of soils. Neural Network World. 2014, 24(3), pp. 249-266.

NAUS D. J. The effect of elevated temperature on concrete materials and structures-a literature review [online]. Oak Ridge: Oak Ridge National Laboratory, 2005 [viewed 2015-01-28]. Research report. Available from:

NEVILLE A.M. Properties of concrete. 4th Edition. New York: John Wiley, 1997.

POKORNÁ N., ŠTEMBERK P. Fuzzy logic model for description of fatigue behavior of concrete. In: Mechanika 2010: Proceedings of the 15th International Conference, Kaunas, Lithuania. 2010, pp. 351-355.

ROY A. F. V., CHENGY M., WUY Y. Time dependent evolutionary fuzzy support vector machine inference model for predicting diaphragm wall deflection. Neural Network World. 2014, 24(2), pp. 193-210.

SEILER J.M., GANZHORN J. Viscosities of corium concrete mixtures. Nuclear Engineering and Design. 1997, 178, pp. 259-268.

SEVÓN T. Molten core – concrete interactions in nuclear accidents: Theory and Design of an Experimental Facility [online]. Espoo, 2005. Master Thesis, VTT Tiedotteita [viewed 2015-01-28]. Available from:

SEVÓN T. A heat transfer analysis of the CCI experiments 1-3. Nuclear Engineering and Design. 2008, 238, pp. 2377-2386.

SEVÓN T., JOURNEAU CH., FERRY L. VULCANO VB-U7 experiment on interaction between oxidic corium and hematite-containing concrete. Annals of Nuclear Energy. 2013, 59, pp. 224-229.

ŠTEMBERK P., et al. Fuzzy modeling of combined effect of winter road maintenance and cyclic loading on concrete slab bridge. Advances in Engineering Software. 2013, 62-63, pp. 97-108.

ŠTEMBERK P., RAINOVÁ A. Simulation of hydration and cracking propagation with temperature effect based on fuzzy logic theory. Mechanika. 2011, 4, pp. 358-362.



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