Japanese Evaluated Nuclear Data Library version 5; JENDL-5

Iwamoto, Osamu; Iwamoto, Nobuyuki; Kunieda, Satoshi; Minato, Futoshi; Nakayama, Shinsuke; Abe, Yutaka*; Tsubakihara, Kosuke*; Okumura, Shin*; Ishizuka, Chikako*; Yoshida, Tadashi*; et al.

Journal of Nuclear Science and Technology, 60(1), p.1 - 60, 2023/01

https://doi.org/10.1080/00223131.2022.2141903

Deep microbial life in high-quality granitic groundwater from geochemically and geographically distinct underground boreholes

Ino, Kohei*; Konno, Yuta*; Kozuka, Mariko*; Hirota, Akinari*; Togo, Yoko*; Fukuda, Akari*; Komatsu, Daisuke*; Tsunogai, Urumu*; Tanabe, Akifumi*; Yamamoto, Satoshi*; et al.

Environmental Microbiology Reports (Internet), 8(2), p.285 - 294, 2016/04

https://doi.org/10.1111/1758-2229.12379

To understand the subsurface biosphere, borehole investigation was conducted for 300-m deep granitic rocks at the Mizunami underground research laboratory, Japan. The initial biomass was the highest with the flourish of aerobic H-oxidizing Hydrogenophaga spp., whereas an uncultivated lineage of the phylum Nitrospirae became predominant after three years with decreasing biomass. The common occurrence of many species of Nitrospirae and Chlorobi phyla at the geographically distinct sites and the exclusive detection of their phylogenetically related environmental sequences from deep groundwaters and terrestrial hot springs, suggest that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.

Response function measurement for 14 MeV neutrons by a CVD single diamond crystal synthesized with high-growth rate

Sato, Kei*; Kakimoto, Akinori*; Kaneko, Junichi*; Fujita, Fumiyuki*; Tsubouchi, Nobuteru*; Mokuno, Yoshiaki*; Chayahara, Akiyoshi*; Sato, Satoshi; Konno, Yuta*; Homma, Akira*; et al.

no journal, , 

As a part of development of diamond energy spectrometers using the C(n,)Be reaction for DT plasma ion temperature measurement, response functions measurement of chemical vapor deposition (CVD) single crystal diamonds for alpha particles and 14 MeV neutrons were carried out. One diamond sample was synthesized by the national institute of advanced industrial science and technology (AIST) aiming at a large size and high-quality substrate for electric device with higher methane concentration of 10%. This diamond crystal was chosen according to intensity of free exciton recombination luminescence. In addition, a CVD single crystal diamond, categorized in "detector grade" synthesized by Element 6 Inc. was evaluated.Response function measurement of 14 MeV neutrons were carried out at the Fusion Neutronic Source facility of Japan Atomic Energy Agency. Energy resolutions of 4.3% and 5.2% for the C(n,)Be reaction were obtained by the two CVD diamond single crystals. In general, energy spectrometer grade CVD diamond single crystals are grown using lower methane concentration, i.e., 1%. However, this results revealed that even higher methane concentration of 10% can grow energy spectrometer grade CVD diamond single crystals.

Hydrogen and carbon isotope geochemistry of freshwater aquifers at the Mizunami Underground Research Laboratory; Implications for ongoing biogeochemical processes in granitic rocks

Konno, Yuta*; Fukuda, Akari; Kozuka, Mariko*; Komatsu, Daisuke*; Tsunogai, Urumu*; Aosai, Daisuke; Mizuno, Takashi; Suzuki, Yohei*

no journal, , 

Our knowledge of biogeochemical processes mediated in those associated with freshwater should be integrated. We collected the groundwater samples from 200 m to 1150 m depths below ground level at Mizunami Underground Research Laboratory located in central Japan. We measured the concentration and both hydrogen and carbon isotopic compositions of dissolved methane, total inorganic carbon (TIC) and molecular hydrogen. The origin of methane could be speculated to be not biogenic CO reduction or acetate fermentation but thermogenic or abiogenic. In contrast, C1/C2+C3 ratios supported biogenic methane production. The 300 m deep samples were enriched in hydrogen and acetate and depleted in sulfate, which is characteristic of acetogenesis. From these results, it is suggested that the production of acetate rather than methane could be dominant biogeochemical processes in the reducing portions of freshwater aquifers in granitic rocks.

Metabolic rates of subsurface microorganisms in a hydrogeochemically characterized granitic aquifer system at the Mizunami Underground Research Laboratory (MIU) in Japan

Fukuda, Akari; Kozuka, Mariko*; Konno, Yuta*; Aosai, Daisuke; Hagiwara, Hiroki; Mizuno, Takashi; Suzuki, Yohei*

no journal, , 

To quantify microbial influences on the hydrogeochemistry of a 99-1169-m deep granitic aquifer system, we developed methodology for sensitive measurements of a variety of aerobic and anaerobic metabolic activities. Briefly, microbial cells were ca. 30-fold concentrated in groundwater by filtration to incubate with electron acceptors. Aerobic respiration was more than 400 umol/L/year at depths of 99 and 175 m and decreased with increasing depth down to 36 umol/L/year at a depth of 1169 m. Nitrate respiration increased from 99 to 308 m (4.3 to 37 umol/L/year) and decreased with increasing depth down to 0.20 umol/L/year. Sulfate respiration ranging from 1.4 to 3.2 umol/L/year was detected only at depths above 200 m. The depletion of O and NO and a gradual decrease in sulfate with increasing depth in the granitic aquifer could be attributed to microbial respirations at rates clarified in this study. Our research was partially founded by Nuclear and Industry Safety Agency.

JAEA/AIST colaborative research project; Development and evaluation of investigation methodology to quantify microbial influences on the deep hydrogeochemical properties

Fukuda, Akari; Mizuno, Takashi; Aosai, Daisuke; Hagiwara, Hiroki; Yamamoto, Yuhei; Shingu, Shinya; Takeno, Naoto*; Suzuki, Yohei*; Konno, Yuta*; Kozuka, Mariko*

no journal, , 

no abstracts in English

Unveiling key players in the geological disposal environment

Suzuki, Yohei*; Fukuda, Akari; Konno, Yuta*; Kozuka, Mariko*; Hagiwara, Hiroki; Aosai, Daisuke; Takeno, Naoto*; Mizuno, Takashi

no journal, , 

Microbial sulfate reduction and sulfur isotope fractionations in deep groundwater at Mizunami Underground Research Laboratory

Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; Suzuki, Yohei*; Fukuda, Akari*; Konno, Yuta*; Tsunogai, Urumu*; Komatsu, Daiyu*; Nagao, Seiya*; Iwatsuki, Teruki

no journal, , 

Isotopic compositions of sulfate, sulfide ions were measured in deep groundwater of Mizunami URL to estimate microbial activity. The results show that relatively large isotopic fractionation between sulfate and sulfide by microbial reduction.

Study on prevention effect of radionuclides adsorbed on the surface of measurement containers

Konno, Yuta*; Maeyama, Takeshi*; Saegusa, Jun; Shinohara, Hirofumi*; Ota, Hiroshi*; Isogai, Keisuke*

no journal, , 

no abstracts in English