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Title: FLASH-6: simulation of top injection emergency core cooling heat transfer tests (LWBR Development Program)

Technical Report ·
DOI:https://doi.org/10.2172/7257395· OSTI ID:7257395

Data from top injection ECCS tests conducted at Columbia University have been analyzed as part of an effort to qualify the FLASH-6 computer program for performing post-blowdown heat transfer calculations for the LWBR Safety Analysis. These experiments, which employed a full-scale fuel assembly with electrical heater rods to simulate an inlet rupture for a pressurized water reactor, provided test conditions and rod cooling mechanisms quite similar to those encountered in the postulated LWBR cold leg break loss-of-coolant accident. Clad temperature predictions were obtained using both the modified Dittus-Boelter and the Dougall-Rohsenow correlations to evaluate beyond CHF heat transfer coefficients. Overall comparisons using the FLASH calculated flow rates indicated that the rod temperature calculations were conservative using either of the heat transfer correlations because virtually none of the coolant was calculated to penetrate the heated test assembly. Heat transfer model comparisons were also performed by adjusting the calculation so that coolant was injected directly into the top of the rod bundle to simulate the experimentally observed flow conditions. Once this downflow was forced, conservative temperature predictions were obtained using the Dougall-Rohsenow correlation, whereas the modified Dittus-Boelter beyond CHF option yielded non-conservative results.

Research Organization:
Bettis Atomic Power Lab. (BAPL), West Mifflin, PA (United States)
DOE Contract Number:
EY-76-C-11-0014
OSTI ID:
7257395
Report Number(s):
WAPD-TM-1296; TRN: 77-013046
Country of Publication:
United States
Language:
English