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Journal Articles

Development of particle collection technique by using bubble breakup phenomenon in venturi tube

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.

Journal Articles

A Numerical simulation method to evaluate heat transfer of fuel debris in air cooling by JUPITER, 2; Validation of porous model for natural convective heat transfer

Uesawa, Shinichiro; Yamashita, Susumu; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Proceedings of 12th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS12) (Internet), 8 Pages, 2022/10

Journal Articles

Experimental investigation of spray cooling behavior in 4$$times$$4 simulated fuel bundle

Nagatake, Taku; Shibata, Mitsuhiko; Yoshida, Hiroyuki; Nemoto, Yoshiyuki; Kaji, Yoshiyuki

Journal of Nuclear Science and Technology, 14 Pages, 2022/00

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

In Fukushima Daiichi Nuclear Power Plant accident, failure of cooling system for spent fuel pool occurred and there was a concern that the spent fuels were damaged. Then a safety measures for SFP cooling in severe accident condition is required. As a countermeasure for SFP severe accident, it is considered that a portable spray is used for SFP cooling in such condition. In this research project, the numerical simulation methods have been developed in order to evaluate the applicability of portable spray system for cooling SFPs. And experiments were also performed in order to get a knowledge of spray cooling phenomena and validation data for the numerical simulation methods. As one of the experiments, a cooling experiment by using 4$$times$$4 simulated fuel assembly were performed and temperature distribution during spray cooling process were measured. In this paper, the results of a cooling experiment are reported.

Journal Articles

Sea water flow boiling heat transfer involving sea salt deposition; Role of deposited sea salt

Koizumi, Yasuo*; Uesawa, Shinichiro; Ono, Ayako; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Nihon Kikai Gakkai Netsu Kogaku Konfarensu 2019 Koen Rombunshu (USB Flash Drive), 1 Pages, 2019/10

no abstracts in English

Journal Articles

Free convective heat transfer experiment to validate air-cooling performance analysis of fuel debris

Uesawa, Shinichiro; Yamashita, Susumu; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 6 Pages, 2018/11

Journal Articles

Measurement of void fraction distribution in a 4$$times$$4 fuel bundle under high pressure condition for validation of two-phase CFD code

Nagatake, Taku; Shibata, Mitsuhiko; Uesawa, Shinichiro; Ono, Ayako; Yoshida, Hiroyuki

Proceedings of 11th Korea-Japan Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-11) (Internet), 3 Pages, 2018/11

In the Fukushima Daiichi Nuclear Power Plant accident, reactor cores were cooled by natural circulation due to pump trip. To investigate the accident progress of the Fukushima Daiichi Nuclear Power Plant, it is important to understand the thermal hydraulic behavior in reactor cores including fuel bundles. Flow rate inside cores was relatively low in the natural circulation conditions, then, thermal-hydraulic behavior in the fuel bundles was different from that in the normal operating conditions. To evaluate thermal hydraulic behavior under the accidental conditions, we are developing the numerical simulation codes named TPFIT and ACE3D. These codes are based on two-phase computational fluid dynamics and can simulate the two-phase flow inside fuel bundles including low flow rate condition. Before applying these codes to the thermal-hydraulic behavior, the applicability of these codes must be confirmed. Then, in this study, in order to obtain a validation data for TPFIT and ACE3D code, thermal hydraulic experiment was performed by using test section with a simulated fuel bundle with 4$$times$$4 unheated rods. In this simulated fuel bundle, there were wire mesh sensors, and void fraction distribution data inside the simulated fuel bundle under high pressure condition (max. 2.6 MPa) was obtained. The one of the advantage of wire mesh sensor is that a void fraction distribution of cross section at the same time can be measured. In this paper, void fraction distribution of two-phase flow in a simulated fuel bundle under high pressure condition are reported.

Journal Articles

Simultaneous measurement of dry patch behavior and surface temperature distribution for copper heat transfer surface with deposition layer in nucleate pool boiling

Uesawa, Shinichiro; Ono, Ayako; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Nihon Kikai Gakkai Netsu Kogaku Konfarensu 2018 Koen Rombunshu (USB Flash Drive), 6 Pages, 2018/10

no abstracts in English

Journal Articles

Measurement of water-steam flow behavior and pressure distribution in venturi scrubber

Uesawa, Shinichiro; Horiguchi, Naoki; Suzuki, Takayuki*; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Proceedings of 12th International Topical Meeting on Nuclear Reactor Thermal-Hydraulics, Operation and Safety (NUTHOS-12) (USB Flash Drive), 11 Pages, 2018/10

Journal Articles

Validation of free-convective heat transfer analysis with JUPITER to evaluate air-cooling performance of fuel debris in dry method

Uesawa, Shinichiro; Yamashita, Susumu; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Mechanical Engineering Journal (Internet), 5(4), p.18-00115_1 - 18-00115_13, 2018/08

Journal Articles

Observation of dry patch behavior on copper heat transfer surface and measurement of surface temperature distribution in nucleate pool boiling

Uesawa, Shinichiro; Ono, Ayako; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Dai-55-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu (USB Flash Drive), 8 Pages, 2018/05

no abstracts in English

Journal Articles

Study on water-vapor two-phase flow behavior in venturi tube

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

Journal Articles

Saturated pool nucleate boiling on heat transfer surface with deposited sea salts

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Journal of Nuclear Engineering and Radiation Science, 3(4), p.041002_1 - 041002_13, 2017/10

Journal Articles

Study on fundamental process of seawater pool nucleate boiling heat transfer

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Thermal Science and Engineering, 25(4), p.65 - 74, 2017/10

no abstracts in English

Journal Articles

Development of numerical simulation method to evaluate heat transfer performance of air around fuel debris, 2; Validation of JUPITER for free convection heat transfer

Uesawa, Shinichiro; Yamashita, Susumu; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 7 Pages, 2017/07

Journal Articles

Study on water-vapor two-phase flow behavior in venturi tube

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

Journal Articles

Study on forced-convective boiling heat transfer of seawater with sea salt deposition

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Nagatake, Taku; Yoshida, Hiroyuki

Konsoryu, 31(2), p.162 - 170, 2017/06

no abstracts in English

Journal Articles

Study on fundamental process of seawater pool nucleate boiling heat transfer

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Dai-54-Kai Nihon Dennetsu Shimpojiumu Koen Rombunshu (CD-ROM), 8 Pages, 2017/05

no abstracts in English

Journal Articles

Study on pool nucleate boiling heat transfer of suspension liquid with deposits on heat transfer surface

Uesawa, Shinichiro; Koizumi, Yasuo; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Thermal Science and Engineering, 25(2), p.17 - 26, 2017/04

no abstracts in English

Journal Articles

Effect of seawater on heat transfer without boiling in internally heated annulus

Uesawa, Shinichiro; Liu, W.; Jiao, L.; Nagatake, Taku; Takase, Kazuyuki; Shibata, Mitsuhiko; Yoshida, Hiroyuki

Nihon Genshiryoku Gakkai Wabun Rombunshi, 15(4), p.183 - 191, 2016/12

no abstracts in English

Journal Articles

Development of air cooling performance evaluation method for fuel debris on retrieval of Fukushima Daiichi NPS by dry method, 3; Heat transfer and flow visualization experiment of free convection adjacent to upward facing horizontal surface

Uesawa, Shinichiro; Shibata, Mitsuhiko; Yamashita, Susumu; Yoshida, Hiroyuki

Proceedings of 10th Japan-Korea Symposium on Nuclear Thermal Hydraulics and Safety (NTHAS-10) (USB Flash Drive), 7 Pages, 2016/11

70 (Records 1-20 displayed on this page)