A study on effects of debris bed prototypicality on coolability
2007 (English)In: Proceedings of the 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH12), 2007Conference paper (Refereed)
This paper is concerned with the modeling and prediction of the coolability of debris beds formed in a hypothetical core-melt accident in a light water reactor (LWR). The focus is placed on analysis of the potential effects of the prototypical configuration and characteristics of the debris beds on its coolability, namely (i) porosity range, (ii) multi-dimensionality, (iii) inhomogeneity, (iv) particle morphology, and (v) heat generation (e.g. volumetric heating vs. local heaters). The analysis results indicate availability of substantial coolability margins compared to previous assessments based on models and experiments using an idealized bed (e.g. ID homogenous debris layer). Notably, the high porosity (up to 70%) of debris beds, obtained in experiments and expected to be the case of prototypical debris beds, could dramatically increase the dryout heat flux by 100% and more, depending on particle size, compared with the dryout heat flux predicted for debris beds with traditionally assumed porosity of approximately 40%. Bed inhomogeneity represented by micro channels in a mini bed is predicted to enhance the dryout heat flux by up to ∼50%, even if the micro channels occupies only a small fraction (e.g., less than 4% of the bed). The effect of coolant side ingress into a multidimensional bed is predicted to enhance the dryout heat flux by more than 40%.
Place, publisher, year, edition, pages
Coolability, Corium debris bed, Dryout heat flux, Severe accident, Two-phase flow
IdentifiersURN: urn:nbn:se:kth:diva-57698ScopusID: 2-s2.0-44349091618ISBN: 0-89448-058-8ISBN: 978-089448058-4OAI: oai:DiVA.org:kth-57698DiVA: diva2:472484
12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH12), Pittsburgh, Pennsylvania, U.S.A. September 30-October 4, 2007
QC 201201132012-01-032012-01-032012-01-13Bibliographically approved