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Natural circulation of water at 1200 psia under heated, local boiling and bulk boiling conditions. Test data and analysis

Technical Report ·
DOI:https://doi.org/10.2172/4201674· OSTI ID:4201674
The natural circulation tests performed and analyzed in this report were conducted at 1200 psia on the Bettis Natural Circulation Loop, No. 29. Tho tests were run with two different single channel test sections (0.101 in x 1 in x 27 in. long and 0.210 in x 1 in. x 27 in- long). Heat fluxes ranged from 50,000 Btu/ hr-ft2 to departure from nucleate boiling and inlet subcooling was fixed at 109° F. The results show that there is no difference between natural and forced circulation pressure drop and riser density. (Other tests recently completed but not reported here show similarly that there is no difference between forced circulation and natural circulation DNB providing there are no large deviations of flow due to instabilities.) The tests also show that loop circulating flows in Loop No. 29 can be predicted quite accurately in single- phase flow. Circulation rates with two-phase flow can be accurately predicted if two-phase entrance and exit losses and steamwater slip ratios are known. Further, flow instabilities were noted under certain conditions and occurred before DNB. With the 0.101 in. x 1 in x 27 in long test section these instabilities were large enough to cause a DNB. However, at the same conditions no apparent instability was noted with the 0.210 in. x 1 in x 27 in. long test section. Some data for slip ratios in two phase flow at inlet velocities less than 1 ft/sec were obtained Additional tests with other channel sizes and at other pressures have been completed and data reduction is in progress.
Research Organization:
Westinghouse Electric Corp. Bettis Plant, Pittsburgh, PA (US)
NSA Number:
NSA-14-000283
OSTI ID:
4201674
Report Number(s):
WAPD-AD-TH-470
Country of Publication:
United States
Language:
English