Research Article
Numerical Study of Natural Circulation Flow in Reactor Coolant System during a Severe Accident
Table 2
Comparison of the main evaluation factors between previous studies and CFD analysis.
| | Contents | Symbol or eq. | EPRI-TR-102818 [9] | NUREG-1781 [7] | Model 1 (present work) | | Geometry | — | Reactor-HL-SG | HL-SG | Reactor-HL-SG | | Method | — | Experiment | CFD | CFD |
| | End of hot leg | Mass flow rate at the end of hot leg (kg/s) | mHL | 0.0599 | 0.0586 (−2.2%) | 0.0610 (1.8%) | | Average temperature (°C) | Hot flow | Th | 159.3 | 155 (−2.7%) | 153.1 (−3.9%) | | Cold flow | Tc | 86.8 | 80.1 (−7.7%) | 80.4 (−7.4%) | | Number of hot tubes | — | 75 | 82 (9.3%) | 70 (−6.7%) | | Number of cold tubes | — | 141 | 134 (−5.0%) | 146 (3.5%) |
| | Tube bundle | Mass flow rate at tubes (kg/s) | mt | 0.1200 | 0.1206 (0.5%) | 0.1199 (-0.1%) | | Heat transfer rate (W) | — | 3,560 | 3,690 (3.7%) | 3,591 (0.9%) | | Average temperature (°C) | Hot tube | Tht | 100.8 | 100 (−0.8%) | 101.2 (0.4%) | | Cold tube | Tct | 64.7 | 64.7 (0.0%) | 64.7 (0.0%) | | Ratio of mass flow rate | mt/mHL | 2.00 | 2.06 (3.0%) | 1.97 (−1.5%) | | Mixed temperature (°C) | Tm | 96.2 | 94.2 (−2.1%) | 94.5 (−1.8%) | | Mixing fraction | f | 0.85 | 0.80 (−5.9%) | 0.77 (−9.4%) |
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HL: hot leg; SG: steam generator.
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