Annals of the Assembly for International Heat Transfer Conference 13

ISBN 1-56700-225-0 / CD 1-56700-226-9

Year 2006

D. J. Euh
Korea Atomic Energy Research Institute, Daejeon, Korea

B. J. Yun
Korea Atomic Energy Research Institute, Daejeon, Korea

Y. J. Youn
Korea Atomic Energy Research Institute, Daejeon, Korea

C.-H. Song
Korea Atomic Energy Research Institute, Daejeon, Korea

Hydraulic phenomena in the downcomer of a conventional pressurized water reactor have an important effect on the transient behavior of a postulated large-break LOCA (LBLOCA). In particular, safety analyses using best-estimate codes show that a downcomer boiling is one of the important phenomena in the postulated LBLOCA because it can degrade the hydraulic head in the downcomer and consequently affect the reflood flow rate for a core cooling. To experimentally identify the thermal hydraulic behavior in the downcomer, a downcomer-boiling test facility, named DOBO, was constructed to simulate a downcomer boiling in the reflood phase of a postulated LBLOCA. The test facility was designed by adopting a full-pressure, full-height, and full-size downcomer-gap approach, which corresponds to a 1/47.08 circumferential part of the APR1400 downcomer. In this study, a visual observation and measurements of the boiling two-phase phenomena are performed. The measured parameters can be divided into global and local ones. The global parameters include the fluid temperature, flow rate, pressure, and average void fraction in the test section. Local steam velocity and void fraction are measured by inserting a local probe and moving it to the desired position by means of a two-dimensionally controlled traversing unit.

NCL-09 pages DOI: 10.1615/IHTC13.p7.90 Download article

Article price - $35.00

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