| Summary: | 博士 === 國立清華大學 === 核子工程學系 === 81 === The study adopts both experimental and time domain analysis
methods to conduct the two-phase system stability phenomena.
The approach to ivestigate the two-phase flow stability
consists of three steps. The first step includes the
establishment of the experiment and the analysis mode, the
verification of the modeling and related papers review. The
experiment uses a low pressure natural circuation loop at the
Institute of Nuclear Energy Research (INER) to investigate
stability phenomenon under natural circulation condition. The
RETRAN model will be established and verifed by experimental
data to assess its ability in carrying out natural circulation
stability alaysis. In our low pressure natural circulation
wxperiments, conter-current or flow patterns transition based
flow oscillation begins when the test section outlet condition
becomes saturated. RETRAN temperautes, satisfactorily
predictions on flow rates, outlet temperautes, and threshold
power leves. However, numerical difficulties were encountered
during flow oscillations and the calculations could not
continue, probably a limitation in the code''s capability. The
ssecond step is three types of BWR stability analysis. In all
cases investigated, the plant operations would be stable under
various stability map using RETRAN02/MOD05 code under natural
circulation conditions forsheng Nuclear Power Plant (KNPP).
Meanwhile, two trandient loci of KNPP recirculation pump trip(
RPT) with decresingdwater enthalpy are also drawn on the
stability map to assessimilar power oscillaton phenomena as
LaSalle-2 event may occur at KNPP. To avoid numerical
oscillation of flow stabilitytime domain analysis, several
sensitivity studies areout. The results indication that both
transient loci have enough stability margins to unstable
boundary an reveal that KNPP''s operations will bestable under
such RPT with decreasing feedwater enthalpy transients.
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