Droplet evaporation characteristics on high-temperature porous surfaces for cooling fuel debris

Yuki, Kohei*; Horiguchi, Naoki; Yoshida, Hiroyuki; Yuki, Kazuhisa*

Proceedings of 31st International Conference on Nuclear Engineering (ICONE31) (Internet), 4 Pages, 2024/11

https://doi.org/10.1115/ICONE31-135281

Fuel debris in the Fukushima Nuclear Power Station is cooled under immersion condition. However, in the event of an unexpected decrease in water level, coolant contacts high-temperature fuel debris having porous structure. In this event, although fuel debris needs to be cooled rapidly, thermal behavior at liquid-solid contact, such as capillary phenomenon, remains unclear. In this paper, as basic research, we evaluate droplet evaporation characteristics after contact with metal porous media with small pores less than 1 mm. In experiment, to obtain life time curve of a droplet, bronze or stainless steel porous media having 1, 40, or 100 m pore diameter are utilized. Experimental results show that Leidenfrost phenomenon is suppressed on the porous surfaces because generated vapor can be discharged from the pores. Further, for bronze porous media, capillary phenomenon is observed as the temperature of the porous media increase because of generation of oxide film having fine structure. On the other hand, due to low wettability of stainless steel porous media, capillary phenomenon does not occur, and the droplet was not sucked and spread into pore. This indicates that rapid cooling by the capillary phenomenon can not be expected if fuel debris has the same characteristics as the stainless steel porous media.

Development of advanced heat removal technology and experimental investigation of the cooling limit; Challenges by porous media, mist cooling, and high-speed swirling flow, JAERI's nuclear research promotion program, H11-037 (Contract research)

Toda, Saburo*; Yuki, Kazuhisa*; Akimoto, Hajime

JAERI-Tech 2004-008, 58 Pages, 2004/03

JAERI-Tech-2004-008.pdf:5.14MB

no abstracts in English

Transient behaviors of gas in thermal insulation media at rapid depressurization

; ; Okamoto, Yoshizo; ;

Journal of Nuclear Science and Technology, 16(10), p.732 - 740, 1979/10

https://doi.org/10.3327/jnst.16.732

no abstracts in English