Effect of bubbly/slug interfacial shear on liquid carryover predicted by RELAP5/MOD2 during reflooding
Analysis of very low flooding rate reflooding experiments and one boiloff experiment in the 33 electrically heated rod bundle NEPTUN at EIR with RELAP5/MOD2/36.02 has shown that the code grossly overpredicts the liquid carryover. Similar results have been reported in the analysis of a large number of boiloff experiments in NEPTUN with TRAC-BD1/MOD1. In this case, the differences between measurements and predictions were attributed to the large bubble/slug interfacial shear in TRAC-BD1 and excellent agreement with the measurements was achieved by implementing in this code a slightly modified version of a new bubbly/slug interfacial shear correlation developed for rod bundles. As far as reflooding is concerned, one of the most crucial parameters for the correct prediction of the rod surface temperature histories is the interfacial shear f/sub i/ in the different flow regimes; it is precisely this term that will largely determine the liquid fraction at a certain axial elevation, and the liquid carryover. In the paper, the authors outline the implementation of the new bubble/slug f/sub i/ correlation in RELAP5/MOD2/36.02 and assess its influence in the liquid carryover in the analysis of low flooding rate experiments in NEPTUN.
- Research Organization:
- EIR, Wuerenlingen, Switzerland
- OSTI ID:
- 6890035
- Report Number(s):
- CONF-861102-
- Journal Information:
- Trans. Am. Nucl. Soc.; (United States), Journal Name: Trans. Am. Nucl. Soc.; (United States) Vol. 53; ISSN TANSA
- Country of Publication:
- United States
- Language:
- English
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Qualification of modifications of interfacial shear and wall heat transfer of RELAP5/MOD2/36. 02 during reflooding
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