Analysis of wall heat capacity effects on core makup tank drain-down behavior in ROSA/AP600 experiments

Conference · Mon Dec 01 04:00:00 EST 1997

OSTI ID:549088

Kondo, Masaya; Yonomoto, Taisuke; Asaka, Hideaki ^[1]

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1. Japan Atomic Energy Research Institute, Ibaraki (Japan); and others

The thermal-hydraulic behavior of the core makeup tank (CMT) during scaled integral experiments on the Westinghouse AP600 reactor design was analyzed using the RELAP5/Mod3 (version 5M5) code. The natural circulation rate through the CMT was predicted well, although the prediction of the thermal stratification in the CMT had a problem due to inability to predict multidimensional mixing in the CMT upper regions. The over-scaled CMT metal mass in the experimental facility affected the CMT drain-down behavior in two experiments: (i) a multiple-failure experiment where the system depressurization became extremely slow due to the simulated failure of the ADS valves; and (ii) a relatively-large break experiment where the CMT started draining before thermal stratification developed in the CMT water inventory. In both experiments, the CMT wall became a heat sink and was a large steam condensation site. This had a effect to limit the CMT drain rate. 6 refs., 15 figs.

• OSTI ID: 549088
• Report Number(s): CONF-970607--Vol.1
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
REACTOR SAFETY
SAFETY INJECTION
TANKS
THERMAL ANALYSIS
TRANSIENTS
WATER COOLED REACTORS