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Kawamura, Takuma; Hasegawa, Yuta; Idomura, Yasuhiro
Proceedings of Joint International Conference on Supercomputing in Nuclear Applications + Monte Carlo 2020 (SNA + MC 2020), p.187 - 192, 2020/10
In order to realize the atmospheric dispersion prediction of pollutants, a fluid simulation by adaptive mesh refinement (AMR) optimized for GPU supercomputer has been developed, and interactive visualization and parameter steering of the simulation results are needed. In this study, we extend particle-based in-situ visualization method for structured grids into AMR, and enables in-situ steering of the simulation parameters by utilizing an in-situ control mechanism via files. By combining the developed method with plume dispersion simulation in urban areas running on a GPU platform, it was shown that human-in-the-loop pollution source search is possible without enormous parameter scanning.
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：4 Percentile：28.67(Geochemistry & Geophysics)no abstracts in English
H and 
O of water in pores extracted by compression method; Effects of closed pores and comparison to direct vapor equilibration and laser spectrometry methodNakata, Kotaro*; Hasegawa, Takuma*; Oyama, Takahiro*; Miyakawa, Kazuya
Journal of Hydrology, 561, p.547 - 556, 2018/06
Times Cited Count：2 Percentile：13.06(Engineering, Civil)no abstracts in English
Nakata, Kotaro*; Hasegawa, Takuma*; Oyama, Takahiro*; Ishii, Eiichi; Miyakawa, Kazuya; Sasamoto, Hiroshi
Geofluids, 2018, p.7823195_1 - 7823195_21, 2018/01
Times Cited Count：5 Percentile：43.35(Geochemistry & Geophysics)A groundwater scenario is one of the scenario for safety assessment of geological disposal of high-level radioactive waste. In the safety assessment for groundwater scenario, the slow groundwater flow for a long-term should be an important factor. In the present study, study on stability of groundwater in the Koetoi and Wakkanai formations of Neogene marine based sedimentary rock at the Horonobe area, Hokkaido was performed by investigating the isotopes of chlorine and helium, and the stable isotopes of water. As the results, the stability of groundwater in deeper part of the Wakkanai formation was suggested due to no direct evidence of meteoric water intrusion during the uplift since ca. 1 Ma. Contrary, the groundwater both in the Koetoi formation and the upper Wakkanai formation would be unstable because the meteoric water intrusion was suggested by paleohydrogeological condition and the results of groundwater dating. Likely the Horonobe area, the accurate dating of groundwater would be difficult due to the complex effects of upward and mixing water derived from diagenesis in the thick sediment formation. However, a comparative procedure using both the results of groundwater dating and paleohydrogeological information would be useful for general evaluation of groundwater flow conditions for the long-term (i.e., check the possibility for long-term stability of groundwater).
Miyakawa, Kazuya; Tamamura, Shuji*; Nakata, Kotaro*; Hasegawa, Takuma*
JAEA-Data/Code 2016-021, 60 Pages, 2017/03
JAEA-Data-Code-2016-021.pdf:3.87MB
JAEA-Data-Code-2016-021-appendix(CD-ROM).zip:0.45MB
The Japan Atomic Energy Agency has been involved in ongoing research in the Horonobe area for the purposes of geoscientific research, and research and development (R&D) on technologies to be used for the geological disposal of high-level radioactive waste. The chemistry of groundwater and dissolved gas from deep boreholes has been obtained since H13 fiscal year for R&D on technologies related to geological characterization. Horonobe Research Institute for the Subsurface Environment (H-RISE) has investigated a resources development on promoting effective use of coal bed buried in Hokkaido including the Horonobe area using microbial communities. The data of dissolved gas from the Horonobe groundwater have also been obtained along with the microbiological research by H-RISE. Central Research Institute of Electric Power Industry (CRIEPI) has conducted R&D on technology of groundwater geochronology which is one of technologies to be used for the geological disposal, and noble gas data from the Horonobe groundwater have been obtained by CRIEPI. This report shows a data set which comprises gas data obtained from the Horonobe underground research project during the period from H13 fiscal year to H27 fiscal year.
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：7 Percentile：31.85(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.
C collected by precipitation and gas-strip methods for dating groundwaterNakata, Kotaro*; Hasegawa, Takuma*; Iwatsuki, Teruki; Kato, Toshihiro
Radiocarbon, 58(3), p.491 - 503, 2016/09
Times Cited Count：4 Percentile：19.43(Geochemistry & Geophysics)Dissolved inorganic carbon (DIC) for C analysis of groundwater is usually extracted by a gas-strip or precipitation method. In this study, the certainty of the two methods for C dating were confirmed. DIC and C concentrations obtained by the gas-strip method were close to the theoretically predicted C value. Conversely, the C value obtained by the precipitation method always showed higher values than the predicted values. The difference in C value between gas-strip and precipitation methods was assumed to arise owing to contamination of modern carbon used in the precipitation method. The applicability of the precipitation method for groundwater should be considered carefully according to the DIC, C concentration of groundwater and purpose of the study being conducted.
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.
Sanada, Yukihisa; Ishii, Masato*; Hasegawa, Ichiro; Kanazawa, Nobuyuki; Chikazawa, Tatsuya*; Momose, Takumaro
NEA/CSNI/R(2010)4 (Internet), p.351 - 370, 2010/11
A criticality accident alarm system (CAAS) was installed in the 1980s as part of criticality safety management at the Tokai Reprocessing Plant (TRP) to reduce the chance of workers being exposed to radiation in the rare case of a criticality accident. From a compliance point of view processing at TRP cannot take place without the criticality monitoring provided by the CAAS. This paper gives an overview of the process of the CAAS being replaced as part of aging management.
Hikinuma, Yuichi; Sanada, Yukihisa; Hasegawa, Ichiro; Kanazawa, Nobuyuki; Kawai, Keiichi*; Momose, Takumaro
no journal, ,
no abstracts in English
Ota, Kunio; Shigeta, Naotaka; Marui, Atsunao*; Uchida, Toshihiro*; Kiho, Kenzo*; Hasegawa, Takuma*
no journal, ,
JAEA commenced a surface-based investigation programme under the collaboration with AIST and CRIEPI, which would focus on the establishment of comprehensive site characterisation technology and the enhancement of its reliability through the characterisation of the geological environment at the coastal region in Horonobe, Hokkaido. Here the programme, particularly background, goal, main issues and timeplan, is overviewed.
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.
He, 
Cl at Horonobe area, HokkaidoNakata, Kotaro*; Hasegawa, Takuma*; Iwatsuki, Teruki
no journal, ,
Groundwater residence time were inferred by He, Cl at Horonobe area, Hokkaido, Japan. Both estimated value based on He and Cl range from 2Ma to 10Ma for the groundwater deeper than -250m S.L. Those values correspond to sedimentation age of rock formations. This indicates the possibility that the groundwaters are in stagnant condition since sedimentation.
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.
Kanazawa, Nobuyuki; Sanada, Yukihisa; Yoshitsugu, Yuichi; Hikinuma, Yuichi; Chikazawa, Tatsuya*; Hasegawa, Ichiro; Momose, Takumaro
no journal, ,
no abstracts in English
C in dissolved organicsNakata, Kotaro*; Hasegawa, Takuma*; Kodama, Hiroki*; Miyajima, Toru*; Hama, Katsuhiro; Iwatsuki, Teruki
no journal, ,
We developed estimation method of groundwater age for uranine-contaminated groundwater sample by using C in dissolved organics. Uranine and natural dissolved organics was divided by DAX-8 resin. This method enables to infer the groundwater age contaminated by drilling fluids.
Amamoto, Ippei; Yokozawa, Takuma; Kobayashi, Hidekazu; Taguchi, Tomitsugu; Hasegawa, Yoshio*; Hishinuma, Yukio*; Yamakawa, Atsushi*
no journal, ,
no abstracts in English
Hama, Katsuhiro; Iwatsuki, Teruki; Nakata, Kotaro*; Kodama, Hiroki*; Hasegawa, Takuma*
no journal, ,
Groundwater residence time can be one of the useful tools to understand regional groundwater flow. The trial groundwater dating has been made using radiocarbon (C) in the organics that dissolved in groundwater.
Hasegawa, Yoshio*; Hishinuma, Yukio*; Amamoto, Ippei; Yokozawa, Takuma; Kobayashi, Hidekazu; Taguchi, Tomitsugu; Yamakawa, Atsushi*; Suzuki, Masashi*
no journal, ,
no abstracts in English
Yamakawa, Atsushi*; Amamoto, Ippei; Yokozawa, Takuma; Kobayashi, Hidekazu; Taguchi, Tomitsugu; Hasegawa, Yoshio*; Hishinuma, Yukio*
no journal, ,
no abstracts in English
