Estimation for mass transfer coefficient under two-phase flow conditions using two gas components

Nanjo, Kotaro; Shiotsu, Hiroyuki; Maruyama, Yu; Sugiyama, Tomoyuki; Okamoto, Koji*

Journal of Nuclear Science and Technology, 60(7), p.816 - 823, 2023/07

https://doi.org/10.1080/00223131.2022.2146015

The Succession of bacterial community structure in groundwater from a 250-m gallery in the Horonobe Underground Research Laboratory

Ise, Kotaro; Sasaki, Yoshito; Amano, Yuki; Iwatsuki, Teruki; Nanjo, Isao*; Asano, Takahiro*; Yoshikawa, Hideki

Geomicrobiology Journal, 34(6), p.489 - 499, 2017/07

https://doi.org/10.1080/01490451.2016.1152329

We investigated the change in bacterial community structure after drilling boreholes, 09-V250-M02 and 09-V250-M03 in the 250 m depth research gallery of Horonobe Underground Research Laboratory (URL). In 09-V250-M02, -Proteobacteria was predominantly detected in the clone library analyses of the groundwater samples conducted immediately after drilling the borehole. All these -Proteobacteria clones are closely related to . which is known as sulfide oxidizing chemoautotrophic bacteria. After four years, the microbial structure was drastically changed and most detected OTUs were uncultured species such as candidate division OP9 and Chloroflexi relatives which are frequently detected in deep-sea sediments.

Changes in microbial community composition and geochemistry during excavation shaft and galleries of the Horonobe Underground Research Laboratory

Amano, Yuki; Sasaki, Yoshito; Nanjo, Isao*; Amamiya, Hiroki; Mizuno, Takashi; Ise, Kotaro; Yoshikawa, Hideki

no journal, , 

Continuous monitoring of groundwater chemistry of the boreholes during the facility construction indicated that the salinity around 140 m have not changed from the beggining to date. Water pressures within the area several tens to hundreds meter from the shafts also went down in process of time. Regarding the chemical disturbance in the area, the redox potencial of the groundwaters in the monitoring boreholes showed reducing condition nevertheless the gallery is in oxidized condition. However, microbial community structure changed considerably from the beggining to date. These results indicate that microbial redox reaction could contribute to maintain of reducing conditions in the groundwater system, despite of hydrochemical disturbance caused by facility construction.