Steady-state performances and scaling analyses for an open flashing-driven natural circulation system

Guo, Xueqing; Sun, Zhongning; Wang, Jianjun; Sui, Yu

doi:10.1016/j.pnucene.2015.11.007

Cited by 13 publications

(2 citation statements)

References 24 publications

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“…It was worthy of mention that the flashing process should include the core section if its elevation was so large that the reduced hydrostatic head could not be neglected. However, in this study, the flashing effect was neglected in the core section due to the relatively short core height in the NMR [9].…”

Section: Flashing Modelmentioning

confidence: 99%

“…Therefore, the safe operation or the system performance would be largely affected by the flashing instability. Although the flashing instability have been widely investigated experimentally and numerically in the last decade [3][4][5][6][7][8][9], the difficulties of predicting the flashing instability still exists due to its complexity. The demand to improve and develop the mechanistic model for the flashing instability becomes much urgent and necessary especially with the advancement of the next generation nuclear plants (NGNP).…”

Section: Introductionmentioning

confidence: 99%

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Modeling of flashing-induced flow instabilities for a natural circulation driven novel modular reactor

Shi

Ishii

2017

Annals of Nuclear Energy

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An analytical study based on frequency domain analysis is presented on the flashing-induced flow instability in a natural circulation test facility, which was designed to investigate the flow instability for a BWR-type novel modular reactor (NMR). To address the flashing phenomena at low pressure conditions, such as initial startup transients or accidents, the liquid enthalpy change in the P-T diagram due to reduced hydrostatic head in the riser or chimney was treated as an axially uniform heat flux. Based on the drift flux model, the system transfer function was obtained through small perturbations about the steady state in the frequency domain. The D-partition method was used to determine the neutral stability boundary in the dimensionless stability plane, which was constituted of the subcooling number and phase change number. From the frequency domain analysis, the flashing stability boundary and the density wave oscillations boundary could be predicted. Some parametric studies had been performed on the system pressure and the inlet flow resistance coefficients in the stability analysis. The results showed that the flashing stability boundary was more sensitive to the system pressure than the density wave oscillations. In addition, the theoretical stability boundaries were benchmarked against the experimental stability boundaries from quasi-steady state tests. Although the general stability boundary agreed well with the experiments, certain discrepancies still existed due to the assumptions of thermal equilibrium in current study. In the future, the thermal non-equilibrium conditions including subcooled boiling will be taken into account in the flashing induced stability analysis.

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Section: Flashing Modelmentioning

confidence: 99%