Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
He/
He ratios observed in the source regionUmeda, Koji; Asamori, Koichi
no journal, ,
no abstracts in English
Niwa, Masakazu; Kurosawa, Hideki; Mizuochi, Yukihiro*; Tanase, Atsushi*
no journal, ,
Fault zone development has the potential to impact regional groundwater flow. Groundwater flow plays an important role in mass transport and nuclide migration. Thus understanding mass transport along fault zones is one of the major subjects for topical issues such as geological disposal of radioactive waste. In this study, we analyzed whole-rock chemical composition of fault rocks from well-studied outcrops of the Atera Fault in central Japan. We particularly focused on REE, U, Th, as an analogue of radionuclides included in high-level radioactive waste. As a result, it is suggested that heterogeneity of host rock lithology presented as mixing of fragments of mafic volcanic rocks in the fault core has a great influence on the material transport in the fault zone, as well as water-rock interaction and clay mineral formation caused by fracturing.
Yamada, Kunimi; Kogiso, Tetsu*; Uesugi, Kentaro*; Hirata, Takafumi*
no journal, ,
no abstracts in English
Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo
no journal, ,
no abstracts in English
Iwatsuki, Teruki; Honda, Teruyuki*; Murakami, Hiroaki
no journal, ,
U, Th and REEs abundances in sedimentary rocks were analyzed to understand the long-term mobility of these elements and to develop the evaluation method of the pragmatic solutes transport path at Horonobe area, Japan. The detail analysis of peculiar points such as fracture and fault as a possible solutes transport path shows the accumulation and leaching of U, Th and REEs at some faults with connection and continuousness at specific depth. The fault and accompanied alteration possibly facilitates to leach and move the heavy-REEs (HREEs) from primary rock. Then those elements seem to have a tendency to concentrate into carbonate mineral vein in the fracture. The some clay-rich fault parts enriches in U, Th and light to medium-REEs (LREE-MREEs) compared with background rock. From the viewpoint of solutes transport, remarkable transport path is fracture and fault (fracture media) rather than rock matrix (porous media) in sedimentary rocks at the area.
Mizuno, Takashi; Aosai, Daisuke; Shingu, Shinya; Yamamoto, Yuhei; Fukuda, Akari; Hagiwara, Hiroki
no journal, ,
no abstracts in English
Nakayama, Hiromasa; Nagai, Haruyasu
no journal, ,
We have developed a local-scale high-resolution atmospheric dispersion model using Large-Eddy Simulation (LES) for the safety assessment of nuclear facilities and emergency responses against accidental or intentional release of radioactive materials such as a terrorist attack within urban areas. In this study, we performed LES of flow and dispersion in an actual urban area and, then, compared with the wind tunnel experimental data.
Murakami, Hiroaki; Amano, Yuki; Kokubu, Yoko; Iwatsuki, Teruki
no journal, ,
C in sedimentary rocks were measured to understand the residence time of groundwater at Horonobe area, Japan. Wakkanai Formation and Koetoi Formation are distributed at the study area. Groundwater samples were collected at -140m and -250m (GL). C concentration in groundwater samples are range from 0.39 to 1.04 pMC. Results of calculations, C in samples are not contamination. Although the C ages are about 40,000 year BP by simply calculation, correlation from influence of dead carbon is necessary.
Kutsuna, Ryosuke*; Otani, Tomoyuki*; Kojima, Satoru*; Enami, Masaki*; Kakamu, Kazuhiko; Wakai, Shoji
no journal, ,
no abstracts in English
Murakami, Makoto*; Kawamura, Makoto*; Makino, Hitoshi; Geshi, Nobuo*; Oikawa, Teruki*; Nishimura, Takuya*; Umeda, Koji; Sasaki, Hisashi*; Seo, Toshihiro; Oi, Takao*
no journal, ,
The prediction technique of the volcanism is requested from the viewpoint of disaster prevention now. The prediction method using the volcanic scenario has been paid to attention. The purpose of this study is to develop the methodology of the volcanic scenario construction that the progress of the volcanic activity is predictable by progressively applying the FEP analysis methodology in the research of HLW geological disposal to the volcanic activity. A basic concept is as follows. We resolve the phenomena to compose the volcanic activity to the single-process referring to past volcanic eruptions. The single-process is arranged to the logical function theory. And, the development of volcanic scenarios is expressed as a chain of the functions. As a result, we developed adaptable volcano scenarios to the purpose. Moreover, it could be expected that the observations are made more effective by feeding back this methodology to the field survey.
Takemi, Tetsuya*; Nakayama, Hiromasa; Nagai, Haruyasu
no journal, ,
The purpose of this study is to propose a numerical approach for quantitative analyses of wind flows in real urban areas. We conduct numerical simulations for strong winds and gusts over the central business district of Tokyo during the passage of Typhoon Melor (2009). The WRF model is used for the meteorological simulation; Mesoscale Analysis data by JMA are used as the initial and boundary conditions. The nesting technique is used to resolve the area including central Tokyo at 60-m grid. The high-resolution temporal and spatial data from the WRF model are then used as the initial and boundary conditions for an LES model. The lower boundary of the LES model is determined by a building-height dataset for the analysis area. A turbulent simulation of wind flows in the realistic urban area is conducted with the LES model. The simulation successfully captures the wind variability and peaks observed at a surface site of JMA.
Maeda, Koshi*; Hasegawa, Yusuke*; Fukushi, Keisuke*; Yamamoto, Yuhei; Aosai, Daisuke; Mizuno, Takashi
no journal, ,
no abstracts in English
Sato, Tatsuhiko; Yasuda, Hiroshi*; Kataoka, Ryuho*; Yashiro, Seiji*; Kuwabara, Takao*; Shiota, Daiko*
no journal, ,
In order to precisely estimate the aircrew doses, the Monte Carlo simulation for air shower is indispensable. We had therefore simulated air showers induced by GCR, using a general-purpose Monte Carlo particle and heavy ion transport simulation code system PHITS, and established a model for calculating the aircrew doses anywhere in the world at the solar quiet time. In this study, we applied our simulation technique to the analysis of air shower induced by SEP, and established a model for estimating the aircrew doses from a given SEP energy spectrum and cutoff latitude. The model is to be incorporated into our developing Warning System of AVIation Exposure to SEP called WASAVIES.
Yamasaki, Seiko; Yamada, Kunimi; Tagami, Takahiro*; Zwingmann, H.*
no journal, ,
no abstracts in English
Matsusue, Kazuyuki; Munakata, Masahiro; Hisada, Kimikazu; Kimura, Hideo
no journal, ,
no abstracts in English
Hisada, Kimikazu; Munakata, Masahiro; Matsusue, Kazuyuki; Kimura, Hideo
no journal, ,
no abstracts in English
Munakata, Masahiro; Hisada, Kimikazu; Kimura, Hideo
no journal, ,
We studied the temporal change of hydraulic conductivity to be considered in the safety assessment of geological disposal facility. Based on the measured geological properties performed in Horonobe area, it is appeared that the correlation between the depth and hydraulic conductivity. Then, we estimated the temporal change of hydraulic conductivity in this area.
Yasue, Kenichi; Tanikawa, Shinichi; Ninomiya, Atsushi*; Tanase, Atsushi*
no journal, ,
We focused on the incised meander scars to be distributed along the river and carried out a study of the estimate technique of the uplift rate using the sediment on the scars. The incised meander scars more than 800 were extracted in Japanese Islands by interpretation of 1:25000 topographical maps. The scars are distributed over various altitudes. As a case study, we studied about uplift using the incised meander scars in an area along Totsukawa River where a typical the scars was distributed over various altitude. The sediment was got by machine digging of the high quality. Sedimentation age was estimated by volcanic ashes analysis. The age of the sediment on the incised meander scars of relative height approximately 90m from the present riverbed is approximately 300-400 thousand years ago. From these results, the uplift rate is estimated at a few ten centimeters for 1,000 years.
Sano, Asami; Komatsu, Kazuki*; Kagi, Hiroyuki*; Nagai, Takaya*; Hattori, Takanori
no journal, ,
-AlOOH, distorted rutile type oxyhydroxide is an important hydrous mineral in the deep earth because it is stable at the lower mantle condition. X-ray diffraction study found the change in the compressibility at high pressure which would be attributed to the symmetrization of hydrogen bond, but there is a difference in the pressure where the compression behaviors change. To investigate the D/H isotope effect on the symmetrization, high pressure neutron diffraction experiments were conducted at SNAP, SNS. The intensity of 120 reflection continues to decrease at high pressure and become almost zero intensity at 6.7 GPa, suggesting the transition from P2
nm to Pnnm as a precursor of the symmetrization. Strong D/H isotope effect was found in the hydrogen bond geometry; O-H distances are longer than O-D whereas H...O distances are shorter than D...O.
Sano, Asami; Komatsu, Kazuki*; Okuchi, Takuo*; Hattori, Takanori
no journal, ,
no abstracts in English