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IODINE REMOVAL EFFICIENCY IN NON-SUBMERGED AND SUBMERGED SELF-PRIMING VENTURI SCRUBBER
Ali, Majid,Yan, Changqi,Sun, Zhongning,Gu, Haifeng,Wang, Junlong,Khurram, Mehboob Korean Nuclear Society 2013 Nuclear Engineering and Technology Vol.45 No.2
The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH) and sodium thiosulphate ($Na2S_2O_3$) in water to remove the gaseous iodine ($I_2$) from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine for submerged and non-submerged operating conditions. In the non-submerged venturi scrubber, only the droplets take part in iodine removal efficiency. However, in a submerged venturi scrubber condition, the iodine gas is absorbed from gas to droplets inside the venturi scrubber and from bubbles to surrounding liquid at the outlet of a venturi scrubber. Experimentally, it is observed that the iodine removal efficiency is greater in the submerged venturi scrubber as compare to a non-submerged venturi scrubber condition. The highest iodine removal efficiency of $0.99{\pm}0.001$ has been achieved in a submerged self-priming venturi scrubber condition. A mathematical correlation is used to predict the theoretical iodine removal efficiency in submerged and non-submerged conditions, and it is compared against the experimental results. The Wilkinson et al. correlation is used to predict the bubble diameter theoretically whereas the Nukiyama and Tanasawa correlation is used for droplet diameter. The mass transfer coefficient for the gas phase is calculated from the Steinberger and Treybal correlation. The calculated results for a submerged venturi scrubber agree well with experimental results but underpredicts in the case of the non-submerged venturi scrubber.
Liu, Xinxing,Qi, Xiangjie,Zhang, Nan,Meng, Zhaoming,Sun, Zhongning Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.3
The small PWR has been paid more and more attention due to its diversity of application and flexibility in the site selection. However, the large core power density, the small containment space and the rapid accident progress characteristics make it difficult to control the containment pressure like the traditional PWR during the LOCA. The pressure suppression system has been used by the BWR since the early design, which is a suitable technique that can be applied to the small PWR. Since the configuration and operating conditions are different from the BWR, the pressure suppression system should be redesigned for the small PWR. Conducting the experiments on the scale down test facility is a good choice to reproduce the prototypical phenomena in the test facility, which is both economical and reasonable. A systematic scaling method referring to the H2TS method was proposed to determine the geometrical and thermohydraulic parameters of the pressure suppression containment response test facility for the small PWR conceptual design. The containment and the pressure suppression system related thermohydraulic phenomena were analyzed with top-down and bottom-up scaling methods. A set of the scaling criteria were obtained, through which the main parameters of the test facility can be determined.
Experiment investigation on flow characteristics of open natural circulation system
Xiangjie Qi,Zichen Zhao,Peng Ai,Peng Chen,Zhongning Sun,Zhaoming Meng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5
Experimental research on flow characteristics of open natural circulation system was performed, tofigure out the mechanism of the open natural circulation behaviors. The influence factors, such as theheating power, the inlet subcooled and the level of cooling tank on the flow characteristics of the systemwere examined. It was shown that within the scope of the experimental conditions, there are five flowtypes: single-phase stable flow, flash and geyser coexisting unstable flow, flash stable flow, flash unstableflow, and flash and boiling coexisting unstable flow. The geyser flow in flash and geyser coexisting unstable flow is different from classic geysers flow. The flow oscillation period and amplitude of the formerare more regular, is a newly discovered flow pattern. By drawing the flow instability boundary diagramand sorting out the flow types, it is found that the two-phase unstable flow is mainly characterized byboiling and flash, which determine the behavior of open natural circulation respectively or jointly. Moreover, compared with full liquid level system, non-full liquid level system is more prone to boilingphenomenon, and the range of heat flux density and undercooling degree corresponding to unstableflow is larger