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Uesawa, Shinichiro; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Konsoryu, 37(1), p.55 - 64, 2023/03
In decommissioning Fukushima Daiichi Nuclear Power Station, the issue is confinement of radioactive aerosols in the primary containment vessel. Although a High Efficiency Particulate Air (HEPA) filter is used to collect the aerosol particles, pretreatment equipment such as a scrubber may be applied to reduce the load of HEPA filters. In the scrubber, the aerosol particles are removed by moving from gas to liquid through gas-liquid interface. Since the collection efficiency (CE) depends on gas-liquid interfacial area, fine bubbles are necessary to obtain high collection efficiency. JAEA developed a new particle removal technique by using bubble breakup phenomenon in a Venturi tube. To confirm usefulness of the technique, we performed the CE measurements and observed gas-liquid two-phase flow in the Venturi tube. In comparison with a straight pipe type, the Venturi type can have removed particles more 1,000 than it. The CE is almost the same as a HEPA filter. In addition, the Venturi type has the enough CE as the pretreatment equipment for various materials of particles such as Kanto loam, SUS and oil. Besides, we clarified that the CE of the Venturi type depended on the gas and liquid flow rates. The CE increases with the increase of the liquid flow rate but decreases with the increase of the gas flow rate. This is because the CE is affected by the bubble breakup phenomenon in the Venturi tube. In the experiment, we confirmed that cavitation number which is the parameter of the bubble breakup was related to the CE of the Venturi type.
Horiguchi, Naoki; Yoshida, Hiroyuki; Abe, Yutaka*
Journal of Nuclear Science and Technology, 56(3), p.278 - 290, 2019/03
Times Cited Count：0 Percentile：0.01(Nuclear Science & Technology)Venturi scrubber (VS) has been installed in NPPs as one of the components of filtered venting systems. It can eliminate fine aerosol particles including fission products from polluted gas. Under extremely high-velocity conditions during severe accident, the data related to the droplet in the VS, which affects decontamination performance, is insufficient. This objective is to obtain the diameter of the extremely high-speed droplets and clarify an applicability of the existing correlations for the diameter. To visualize the extremely high-velocity droplet, an optical system with high frame rate and high resolution was developed. Visualization experiment using the VS under air-water condition was conducted, and droplet diameter distributions and Sauter mean diameter (SMD) were obtained. By comparing experimental data with values evaluated by existing correlations, it was clarified that the Nukiyama-Tanasawa equation can evaluate the SMD with good accuracy in the gas velocity range 82-250 m/s.
Uesawa, Shinichiro; Horiguchi, Naoki; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Nihon Kikai Gakkai Rombunshu (Internet), 84(859), p.17-00392_1 - 17-00392_10, 2018/03
no abstracts in English
Uesawa, Shinichiro; Horiguchi, Naoki; Shibata, Mitsuhiko; Yoshida, Hiroyuki
Dai-22-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 6 Pages, 2017/06
no abstracts in English
Horiguchi, Naoki; Yoshida, Hiroyuki; Uesawa, Shinichiro; Abe, Yutaka*
Dai-22-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 4 Pages, 2017/06
Venturi scrubber is installed in nuclear power plant as a component of filtered venting system and used to remove small aerosols with fission products. There is, however, no method to estimate its decontamination performance in the assumed operating pressure range. In this study, we establish a method to estimate the decontamination performance based on mechanistic thermal hydrodynamic simulation code and report simulated results of the thermal hydrodynamics and decontamination performance in the pressure range in the pressure range in actual environments. With decrease in inlet pressure of the Venturi scrubber, gas flow velocity at the throat of it is suppressed, liquid flow velocity in a hole of it by self-priming changes and the decontamination factor changes were obtained. Also, with larger the aerosol diameter, the decontamination factor become larger was obtained.
Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kaneko, Akiko*; Abe, Yutaka*
Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11
Horiguchi, Naoki; Yoshida, Hiroyuki; Kaneko, Akiko*; Abe, Yutaka*
Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 6 Pages, 2014/07
no abstracts in English
Hayashi, Takumi; Nakamura, Hirofumi; Iwai, Yasunori; Kawamura, Yoshinori; Isobe, Kanetsugu; Yamada, Masayuki; Suzuki, Takumi; Kurata, Rie; Edao, Yuki; Perevezentsev, A.*
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Yoshida, Hiroyuki; Uesawa, Shinichiro; Horiguchi, Naoki; Abe, Yutaka*
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Horiguchi, Naoki; Yoshida, Hiroyuki; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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Horiguchi, Naoki; Yoshida, Hiroyuki; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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Nakao, Yasuhiro*; Yoshida, Hiroyuki; Horiguchi, Naoki; Kaneko, Akiko*; Abe, Yutaka*
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Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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Nakao, Yasuhiro*; Horiguchi, Naoki; Yoshida, Hiroyuki; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kanagawa, Tetsuya*; Kaneko, Akiko*; Abe, Yutaka*
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Horiguchi, Naoki; Yoshida, Hiroyuki; Nakao, Yasuhiro*; Kaneko, Akiko*; Abe, Yutaka*
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Uesawa, Shinichiro; Horiguchi, Naoki; Suzuki, Takayuki*; Shibata, Mitsuhiko; Yoshida, Hiroyuki
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Uesawa, Shinichiro; Horiguchi, Naoki; Shibata, Mitsuhiko; Yoshida, Hiroyuki
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