The effects of debris bed's prototypical characteristics on corium coolability in a LWR severe accident
2010 (English)In: Nuclear Engineering and Design, ISSN 0029-5493, E-ISSN 1872-759X, Vol. 240, no 3, 598-608 p.Article in journal (Refereed) Published
This paper is concerned with coolability assessment of a debris bed formed in fuel coolant interactions (FCIs) during a hypothetical severe accident in a light water reactor (LWR). The focus is placed the potential effect of the bed's prototypical characteristics on its coolability, in terms of (i) porosity range, (ii) multi-dimensionality, (iii) inhomogeneity, (iv) particle morphology, and (v) heat generation method (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 configuration (e.g. 1 D homogenous debris layer). Notably, high porosity (up to 70%) of debris beds, obtained in experiments and expected to be the case of prototypical debris beds, could 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 similar to 50%, even if the micro-channels occupy only a small volume 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 up to 40% for the beds analyzed.
Place, publisher, year, edition, pages
2010. Vol. 240, no 3, 598-608 p.
2-phase flow, porous bed, model, dryout
Engineering and Technology
IdentifiersURN: urn:nbn:se:kth:diva-19279DOI: 10.1016/j.nucengdes.2009.10.026ISI: 000275151200016ScopusID: 2-s2.0-74849086826OAI: oai:DiVA.org:kth-19279DiVA: diva2:337326
QC 201005252010-08-052010-08-052011-01-21Bibliographically approved