Surrogate Models for Debris Bed Dryout
2013 (English)In: The 15th International Topical Meeting on Nuclear Reactor Thermal - Hydraulics, NURETH-15, 2013Conference paper (Refereed)
The problem of debris bed coolability is important for nuclear power plant severe accident management strategies which employ corium melt fragmentation in a deep pool of water as a means to terminate the accident progression. This work is concerned with development of computationally efficient methods for analysis of corium debris bed coolability. To evaluate the likelihood of severe accident progression due to reheating and remelting of the debris it is important to determine conditions for onset of the dryout in the bed. In the case of a flat one-dimensional debris bed, such conditions are called Dryout Heat Flux (DHF). The DHF is determined by the properties of the bed such as mean particle diameter, porosity, etc., by decay heat power and system pressure and can be obtained analytically. For non-flat configurations of the bed, numerical solution of the multidimensional problem of heat and mass transfer in a porous heat generating media is required in order to find the coolability boundary. In this paper we develop the general functional form of coolability conditions for arbitrary-shape debris beds. It is shown that the DHF concept for a flat debris bed can be extended naturally to multidimensional cases. On the basis of this analysis, a surrogate model is proposed which provides approximation of the coolability boundary, enabling fast calculation of the dryout conditions. The surrogate models enables application of the sensitivity, uncertainty and risk analysis of debris bed coolability.
Place, publisher, year, edition, pages
IdentifiersURN: urn:nbn:se:kth:diva-139103OAI: oai:DiVA.org:kth-139103DiVA: diva2:683813
The 15th International Topical Meeting on Nuclear Reactor Thermal - Hydraulics, NURETH-15, Pisa, Italy, May 12-17 2013
QC 201403042014-01-072014-01-072014-03-04Bibliographically approved