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Nakata, Kotaro*; Hasegawa, Takuma*; Solomon, D. K.*; Miyakawa, Kazuya; Tomioka, Yuichi*; Ota, Tomoko*; Matsumoto, Takuya*; Hama, Katsuhiro; Iwatsuki, Teruki; Ono, Masahiko*; et al.
Applied Geochemistry, 104, p.60 - 70, 2019/05
Times Cited Count：9 Percentile：38.79(Geochemistry & Geophysics)no abstracts in English
He and 
C dating in a granite, Tono area, central JapanHasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Goto, Kazuyuki*; Kashiwaya, Koki*; Hama, Katsuhiro; Iwatsuki, Teruki; Kunimaru, Takanori*; Takeda, Masaki
Geochimica et Cosmochimica Acta, 192, p.166 - 185, 2016/11
Times Cited Count：10 Percentile：38.79(Geochemistry & Geophysics)Groundwater dating was performed simultaneously by the He and C methods in granite of the Tono area in central Japan. Groundwater was sampled at 30 packed-off sections of six 1000-m boreholes. He concentrations increased and C concentrations decreased along a groundwater flow path on a topographic gradient. He ages were calculated by using the in situ He production rate derived from the porosity, density, and U and Th content of the rock, neglecting external flux. The linear relation between the He ages and the noncorrected C ages, except in the discharge area. Simultaneous measurements make it feasible to estimate the accumulation rate of He and initial dilution of C, which cannot be done with a single method. Cross-checking groundwater dating has the potential to provide more reliable groundwater ages.
H, CFCs and SF
as trace materialsHagiwara, Hiroki; Iwatsuki, Teruki; Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*
Nihon Suimon Kagakkai-Shi, 45(2), p.21 - 38, 2015/07
This study evaluates a method to estimate shallow groundwater intrusion in and around a large underground research facility (Mizunami Underground Research Laboratory - MIU). Water chemistry, stable isotopes (
D and 
O), tritium (H), chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF) in groundwater were monitored around the facility (from 20 m down to a depth of 500 m), for a period of 5 years. The results show that shallow groundwater inflows into deeper groundwater at depths of between 200-400 m. In addition, the content of shallow groundwater estimated using H and CFC-12 concentrations is up to a maximum of about 50%. This is interpreted as the impact on the groundwater environment caused by construction and operation of a large facility over several years. The concomitant use of H and CFCs is an effective method to determine the extent of shallow groundwater inflow caused by construction of an underground facility.
Hama, Katsuhiro; Iwatsuki, Teruki; Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Goto, Kazuyuki*
no journal, ,
The dating of groundwater has been carried out by the measurement of radionuclides in groundwater in and around the Mizunami underground research laboratory.
Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Goto, Kazuyuki*; Kashiwaya, Koki*; Hama, Katsuhiro
no journal, ,
The groundwater flow velocity is one of the important items in the safety assessment for the HLW disposal. Generally, it is too difficult to measure the groundwater flow velocity directly. Therefore, to determine the groundwater age by radio active isotopes are effective. However, there are some problems to apply the metrology to the natural samples. For example, because the ratio of Carbon isotope changes by dissolving of the carbonate mineral and resolving the organic materials, the development of the technique for correcting this is needed. In this study, the groundwater ages are measured by He and C, etc. and compared these results as a joint research with Central Research Institute of Electric Power Industry.
Nakata, Kotaro*; Hasegawa, Takuma*; Tomioka, Yuichi*; Tanaka, Yasuharu*; Hama, Katsuhiro; Iwatsuki, Teruki
no journal, ,
The technology development of groundwater dating has been carried out as a part of CRIEPI-JAEA collaboration. The carbon-14 in the organic matter dissolved in groundwater is used to estimate groundwater age. The estimated age is almost same as the age that estimated by the He-4 in groundwater. This suggested that the age estimation by carbon-14 in organic matter can be useful tool to enhance the reliability of the data on groundwater age.
H, CFCs and SF as trace materialsHagiwara, Hiroki; Iwatsuki, Teruki; Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*
no journal, ,
This study evaluates a method to estimate shallow groundwater intrusion in and around a large underground research facility (Mizunami Underground Research Laboratory - MIU). Water chemistry, stable isotopes (D and O), tritium (H), chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF) in groundwater were monitored around the facility (from 20 m down to a depth of 500 m), for a period of 5 years. The results show that shallow groundwater inflows into deeper groundwater at depths of between 200-400 m. In addition, the content of shallow groundwater estimated using H and CFC-12 concentrations is up to a maximum of about 50%. This is interpreted as the impact on the groundwater environment caused by construction and operation of a large facility over several years. The concomitant use of H and CFCs is an effective method to determine the extent of shallow groundwater inflow caused by construction of an underground facility.
Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Hama, Katsuhiro; Iwatsuki, Teruki; Kato, Toshihiro*; Hayashida, Kazuki
no journal, ,
Groundwater dating using C, He, noble gas method was conducted in Mizunami Underground Research laboratory. The availability of degassing method for , flux estimation method for He were examined. It was identified that the groundwater have been derived in glacial age. The integration of distinct dating method is available to estimate precise age of groundwater.
Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Hama, Katsuhiro; Iwatsuki, Teruki; Kato, Toshihiro*; Hayashida, Kazuki
no journal, ,
no abstracts in English
Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Hama, Katsuhiro; Iwatsuki, Teruki; Kato, Toshihiro*; Hayashida, Kazuki
no journal, ,
Groundwater dating was conducted to Mizunami Underground Research Laboratory (MIU). C age and He age were estimated about 20,000 years around MIU. The estimation of noble gas temperature is also conducted. The estimated recharge temperature is around 6
C. This temperature is about 9C cooler than present annual average temperature, which agree with estimation of modern analog method conducted near MIU.
Hasegawa, Takuma*; Nakata, Kotaro*; Tomioka, Yuichi*; Ota, Tomoko*; Okamoto, Shunichi*; Hama, Katsuhiro; Watanabe, Yusuke; Iwatsuki, Teruki
no journal, ,
no abstracts in English
