AUTHOR=Liu Wei , Peng Shinian , Jiang Guangming , Liu Yu 

TITLE=Investigation on Rod Bundle CHF Mechanistic Model for DNB and DO Prediction Under Wide Parameter Range

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2021.620970

DOI=10.3389/fenrg.2021.620970

ISSN=2296-598X

ABSTRACT=For water cooled reactor, the key thermal-hydraulic parameters span a wide range corresponding to different CHF regimes. Under accident conditions, due to the flow patterns transition and interchannel mixing effect, the corresponding CHF can transfer from DO regime to DNB regime. In order to continuously and accurately predict DNB and DO regime CHF in wide parameter range for rod bundle channel, a comprehensive CHF mechanistic model covering the DNB and DO regime CHF prediction is established. Based on the rod bundle CHF-regime criterion, the comprehensive CHF model combined the DNB regime CHF mechanistic model of superheated liquid layer depletion under turbulence fluctuation bubbles with the mature DO regime CHF mechanistic model. Furthermore, the comprehensive CHF model is validated with 5×5 rod bundle CHF experimental data independently obtained by Nuclear Power Institute of China (NPIC). The results show that the calculated P/M are evenly distributed near 1, and the maximum mean error is within ±22%. The distribution of M/P with local pressure, mass flux and quality, and the distribution of predicted flux P with experimental measured flux M have no obvious systematic bias. This indicate that the comprehensive CHF mechanistic model can accurately predict DNB and DO regime CHF in rod bundle channel considering the effects such as heating length, mixing strength, cold wall and axial non-uniform heating on CHF prediction.