Experimental investigation of liquid entrainment in AP1000 ADS-4 branch line with air–water

• Published in: Experimental thermal and fluid science 2014-09, Vol.57, p.317-323
• Main Authors: Sun, D.C., Xiang, Y., Zhang, J., Tian, W.X., Zhang, P., Qiu, S.Z., Su, G.H.
• Format: Article
• Language: English
• Subjects: ADS-4 branch line; Applied sciences; Computational fluid dynamics; Containment; Coolants; Depressurization; Energy; Energy. Thermal use of fuels; Entrainment; Exact sciences and technology; Fission nuclear power plants; High speed cameras; Installations for energy generation and conversion: thermal and electrical energy; Liquid entrainment rate; Liquids; LOCA; Onset of entrainment; Visualization experiments
• ISSN: 0894-1777; 1879-2286
• DOI: 10.1016/j.expthermflusci.2014.05.015

•ADETEL facility scaled after AP1000 with a ratio of 1:5.6 was constructed.•Visualization tests were conducted to gain more entrainment details.•Entrainment onset and entrainment rate data were collected and analyzed.•Experimental data were compared with available data and correlations.•AP1000 has a higher safety performance than AP600 during ADS-4 depressurization. ADS-4 branch line provides a controlled depressurization of the Westinghouse AP600/AP1000 primary loop during a small break LOCA. However, the coolant will be entrained to the containment simultaneously which leads to the loss of liquid inventory. ADS-4 Depressurization and Entrainment TEst Loop (ADETEL) scaled after AP1000 was constructed and visualization experiments were conducted to investigate the entrainment phenomenon at the ADS-4 tee branch line. Entrainment phenomena were recorded by high speed camera and analyzed in detail. The entrainment onset and stabilized entrainment rate data were collected and compared with available data. Discrepancies were found between ADETEL experimental data and available data due to the difference of experimental conditions and test section geometric configuration. The test data reveals that the tee branch liquid entrainment model used in RELAP5 cannot estimate the ADS-4 entrainment for AP1000 accurately and therefore more practicable model should be developed. The ADETEL data also manifest that AP1000 has a higher degree of safety performance during ADS-4 branch depressurization process than AP600 design.