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Machida, Masahiko; Kato, Koichiro*; Shiga, Motoyuki
Journal of Chemical Physics, 148(10), p.102324_1 - 102324_11, 2018/03
Times Cited Count:19 Percentile:70.02(Chemistry, Physical)The isotopologs of liquid water, HO, DO, and TO, are studied systematically by first principles PIMD simulations, in which the whole entity of the electrons and nuclei are treated quantum mechanically. The simulation results are in reasonable agreement with available experimental data on isotope effects, in particular, on the peak shift in the radial distributions of HO and DO and the shift in the evaporation energies. It is found that, due to differences in nuclear quantum effects, the H atoms in the OH bonds more easily access the dissociative region up to the hydrogen bond center than the D (T) atoms in the OD (OT) bonds. The accuracy and limitation in the use of the current density-functional-theory-based first principles PIMD simulations are also discussed. It is argued that the inclusion of the dispersion correction or relevant improvements in the density functionals are required for the quantitative estimation of isotope effects.
Sasaki, Shinji; Maeda, Koji; Furuya, Hirotaka*
Journal of Nuclear Science and Technology, 55(3), p.276 - 282, 2018/03
Times Cited Count:3 Percentile:30.05(Nuclear Science & Technology)Tsuchiya, Tomoki*; Kobayashi, Ryota*; Kubota, Takahide*; Saito, Kotaro*; Ono, Kanta*; Ohara, Takashi; Nakao, Akiko*; Takanashi, Koki*
Journal of Physics D; Applied Physics, 51(6), p.065001_1 - 065001_7, 2018/02
Times Cited Count:10 Percentile:45.99(Physics, Applied)Kamemura, Katsumi*; Aoyagi, Kazuhei; Nago, Makito*; Sugawara, Kentaro*
Dai-45-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.43 - 48, 2018/01
In situ stress state is very important for the design of deep underground facility of high-level radioactive waste disposal repository. This study establishes a practical and effective method for estimating in situ stress state based on the measured convergence and detailed geological observations during gallery excavation. The convergence was measured in various directions of the loop gallery at 350m depth of the Horonobe URL; this allows determination of the stress state corresponding to the rock mass behavior in 120m 200m area. In situ stress state estimated by the back analysis considering existing faults and fractures showed a good agreement with that of estimated from hydraulic fracturing method.
Niunoya, Sumio*; Hata, Koji*; Uyama, Masao*; Aoyagi, Kazuhei; Wakasugi, Keiichiro
Dai-45-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.226 - 231, 2018/01
The objective of this research is to investigate the long-term hydro-mechanical behavior of rock mass around the shaft in the Horonobe Underground Research Laboratory (URL). The long-term monitoring has been carried out by optical AE sensors, optical water pressure sensors, and optical temperature sensors below 350m depth of the shaft in the Horonobe URL. From the first analytical results, it was too hard to discriminate the uncleared AE wave by using the resonant characteristic. Thus, at this time, we tried to reanalysis by using the half width of spectrum, we could discriminate it correctly as AE from the breaking of rock.
Nakata, Kotaro*; Hasegawa, Takuma*; Oyama, Takahiro*; Ishii, Eiichi; Miyakawa, Kazuya; Sasamoto, Hiroshi
Geofluids, 2018, p.7823195_1 - 7823195_21, 2018/01
Times Cited Count:9 Percentile:57.47(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).
Choi, B.; Nishida, Akemi; Itoi, Tatsuya*; Takada, Tsuyoshi*
Geosciences (Internet), 8(1), p.1_1 - 1_22, 2018/01
After the Tohoku earthquake in 2011, we observed that aftershocks tended to occur in a wide region after such a large earthquake. These aftershocks resulted in secondary damage or delayed rescue and recovery activities. However, it is difficult to evaluate the hazards of an aftershock before the main shock due to various uncertainties. For possible great earthquakes, we must make decisions based on such uncertainties, and it is important to quantify the various uncertainties. We previously proposed a probabilistic aftershock occurrence model that is expected to be useful to develop plans for recovery activities after future large earthquakes. In this paper, engineering applications of the proposed approach for probabilistic aftershock hazard analysis are shown for demonstration purposes. One application is to use aftershock hazard maps to plan recovery activities. Another application is to derive load combination equations of the load and resistance factor design (LRFD) considering the simultaneous occurrence of tsunamis and aftershocks for the tsunami-resistant design of tsunami evacuation buildings and nuclear facilities.
Ino, Kohei*; Hernsdorf, A. W.*; Konno, Yuta*; Kozuka, Mariko*; Yanagawa, Katsunori*; Kato, Shingo*; Sunamura, Michinari*; Hirota, Akinari*; Togo, Yoko*; Ito, Kazumasa*; et al.
ISME Journal, 12(1), p.31 - 47, 2018/01
Times Cited Count:49 Percentile:91.33(Ecology)In this study, we found the dominance ofanaerobic methane-oxidizing archaea in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock.
Sakurai, Hiroshi*; Shinohara, Atsushi*; Koura, Hiroyuki; Kamigaito, Osamu*; Morimoto, Koji*; Haba, Hiromitsu*; Enyo, Hideto*
Isotope News, (特別号2), p.2 - 14, 2018/01
no abstracts in English
Kikuchi, Shin; Koga, Nobuyoshi*
Journal of Thermal Analysis and Calorimetry, 131(1), p.301 - 308, 2018/01
Times Cited Count:8 Percentile:34.02(Thermodynamics)Under postulated accidental condition of sodium-cooled fast reactor (SFR), liquid sodium spill into the floor may lead to fail the steel liner resulting in sodium-concrete reaction (SCR). In this study, the sodium hydroxide (NaOH)-silica (SiO) reaction as one of possible secondary stage reactions was investigated for safety assessment of SFR. Thermal behavior of NaOH-SiO reaction such as reaction onset was determined using a differential scanning calorimetry (DSC). As a result of DSC measurement, it was revealed that NaOH-SiO reaction occurs as rapid reaction right after NaOH melting at 583 K. Therefore, it was expected that NaOH-SiO reaction is dominant in the time frame of secondary stage of SCR if significant amount of NaOH has been generated during the initial stage reaction.
Watanabe, Takahiro; Kokubu, Yoko; Murakami, Hiroaki; Iwatsuki, Teruki
Limnology, 19(1), p.21 - 30, 2018/01
Times Cited Count:11 Percentile:53.29(Limnology)Rare earth element (REE) patterns in natural water and geological samples provides information on changes in past environmental conditions, such as redox changes and material cycles; however, quantitative analysis of REEs in these samples is complicated because of relative low content and mass interference from barium oxide in the inductively coupled plasma mass spectrometry (ICP-MS) analyses. In this study, we adopted onsite solid-phase extraction and preconcentration methods for REEs using an iminobisacetic acid-ethylenediaminetriacetic acid chelate resin for the analyses. Standard reference materials, natural ground water, and spring water samples were used for the evaluation of these methods. The REE patterns in the natural water samples were in good agreement with those obtained using previous methods. Therefore, it was deduced that onsite solid-phase extraction using chelate resin is a rapid and simple preparation technique for REE analyses.
Yamaguchi, Masatake
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(1), p.30 - 34, 2018/01
no abstracts in English
Tamai, Hiroshi; Tazaki, Makiko; Suda, Kazunori
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(1), p.25 - 29, 2018/01
IAEA Low Enriched Uranium Bank, which is one of international management initiatives of nuclear materials operated by IAEA, will be realized soon. During increasing concern on proliferation risk of sensitive nuclear technologies as well as in this century the potential acquisition by terrorists, the IAEA bank will offer the fuel assurance aiming at decreasing incentive for acquiring those sensitive technologies. Throughout the argument on the criteria for the fuel supply, the bank site and its requirement have been established and will be in operation next year. The background, significance, and development of this initiative are described.
Aoyama, Michio*; Yamazawa, Hiromi*; Nagai, Haruyasu
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(1), p.46 - 50, 2018/01
no abstracts in English
Koura, Hiroyuki; Minato, Futoshi; Iimura, Hideki
Nihon Genshiryoku Gakkai-Shi ATOMO, 60(1), p.35 - 40, 2018/01
no abstracts in English
Kanno, Ryutaro*; Nunami, Masanori*; Satake, Shinsuke*; Matsuoka, Seikichi; Takamaru, Hisanori*
Nuclear Fusion, 58(1), p.016033_1 - 016033_7, 2018/01
Times Cited Count:0 Percentile:0.01(Physics, Fluids & Plasmas)The electron heat transport in a torus plasma which involves a radially-bounded ergodic region, where flux surfaces are partially destroyed by perturbative magnetic fields, is studied. In this paper, we have demonstrated that the radial heat conduction by the particles' parallel motion is reduced by trapped particles.
Hattori, Taisuke; Sakai, Hironori; Tokunaga, Yo; Kambe, Shinsaku; Matsuda, Tatsuma*; Haga, Yoshinori
Physical Review Letters, 120(2), p.027001_1 - 027001_5, 2018/01
Times Cited Count:12 Percentile:64.96(Physics, Multidisciplinary)Kowatari, Munehiko; Zutz, H.*; Hupe, O.*
Radiation Protection Dosimetry, 178(1), p.48 - 56, 2018/01
Times Cited Count:0 Percentile:0.01(Environmental Sciences)In high energy photon reference fields the value of the air kerma rate is determined by using ionization chambers. From the charge collected inside the ionization chamber the dose can be calculated using a set of calibration and correction factors according to ISO 4037-2. A crucial parameter is the correction for the attenuation and scattering of the primary radiation due to the chamber wall. This parameter can be determined using Monte Carlo calculations. The evaluation of the factor was performed for a commercially available ionization chamber of the type Victoreen 550-3 under different build-up conditions. The results were verified by measurements in the R-F high energy photon fields according to ISO 4037-1 at the Physikalisch-Technische Bundesanstalt (PTB) and the Japan Atomic Energy Agency (JAEA).
Yamashita, Susumu; Ina, Takuya*; Idomura, Yasuhiro; Yoshida, Hiroyuki
Dai-31-Kai Suchi Ryutai Rikigaku Shimpojiumu Koen Rombunshu (DVD-ROM), 7 Pages, 2017/12
no abstracts in English
Kadowaki, Masanao; Nagai, Haruyasu; Terada, Hiroaki; Katata, Genki*; Akari, Shusaku*
Energy Procedia, 131, p.208 - 215, 2017/12
Times Cited Count:4 Percentile:90.81(Energy & Fuels)When radioactive materials are released into the atmosphere due to nuclear accidents, numerical simulations that can reproduce temporal and spatial distribution of radioactive materials are useful to provide the information for emergency responses and radiological dose assessment. In this study, we attempt to improve the atmospheric dispersion simulation using an advanced meteorological data assimilation method and reconstruct the spatiotemporal distribution of radioactive materials released due to the Fukushima Daiichi Nuclear Power Station (FDNPS) accident. The atmospheric dispersion simulations were carried out by the Lagrangian particle dispersion model GEARN developed by Japan Atomic Energy Agency. To obtain meteorological fields for GEARN calculation, we used the Weather Research and Forecasting model WRF with meteorological data assimilation using four-dimensional variational method (4D-Var). GEARN calculations of the surface deposition and air concentration of radionuclides were compared with measurements. In the area close to FDNPS, the spatial distribution of the deposition of Cs-137 and I-131 simulated by GEARN agreed with the measured one. The accuracy of modeled deposition in northwest and south directions from FDNPS was particularly improved. This results were mainly attributed to the better reproducibility of wind field by using the meteorological data assimilation with 4D-Var. The improvement of the accuracy of modeled deposition distribution of Cs-137 in the East Japan area was also apparent under the meteorological fields modified by 4D-Var. The information of atmospheric dispersion processes reconstructed in this study is used for updating the existing assessment of radiological dose resulting from the FDNPS accident based on atmospheric simulations by our previous studies. It can also provide useful suggestions to make emergency response plans for nuclear facilities in Japan.
Hamuza, E.-A.; Nagai, Haruyasu; Sagara, Hiroshi*
Energy Procedia, 131, p.279 - 284, 2017/12
Times Cited Count:1 Percentile:61.21(Energy & Fuels)In this study we would like to propose a method to use atmospheric dispersion simulations by WSPEEDI for consideration of crisis management on radionuclide dispersion from a nuclear power plant. WSPEEDI can simulate and output crucial information regarding environmental distribution of radionuclides and weather pattern for nuclear emergency countermeasures, thus this study will make use of its output to display the effective information for evacuation planning from a radionuclide dispersion. We will be assembling database of atmospheric dispersion outputs for one year by using WSPEEDI for a nuclear facility, then the database will be analysed to make the summary that has useful information for nuclear emergency managements. WSPEEDI outputs are converted into numeric information showing dispersion characteristics so that users can understand WSPEEDI predictions easily.
Onishi, Takashi; Sekioka, Ken*; Suto, Mitsuo*; Tanaka, Kosuke; Koyama, Shinichi; Inaba, Yusuke*; Takahashi, Hideharu*; Harigai, Miki*; Takeshita, Kenji*
Energy Procedia, 131, p.151 - 156, 2017/12
Times Cited Count:11 Percentile:98.3(Energy & Fuels)no abstracts in English
Sakamoto, Yoshiaki
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(2), p.141 - 146, 2017/12
Some research reactors are under decommissioning or preparation for application of decommissioning license for regulation authority in our country. The reasonable treatment and disposal of dismantling waste is important for decommissioning of research reactors. Therefore, in this paper, JAEA's approach of the treatment and disposal of dismantling waste was introduced from the point of view of disposal of low level radioactive waste arising from research, industrial and medical facilities.
Ishihara, Masahiro
Genshiryokuyo Tanso, Kokuen Zairyo; Kiso To Oyo, p.10 - 18, 2017/12
Books summarizing the basic contents of nuclear carbon and graphite materials are seen in overseas, however, there is no book describing the whole aspect of the materials in Japan. Therefore, we describe fundamental matters on the materials in a wide range from basic to application. Here, we include also technical information necessary for structural design and structural integrity evaluation of the materials used in the graphite-moderated high temperature helium gas-cooled reactor. This is an introduction useful for students and graduate students, researchers and engineers, and experts who want to learn the whole issues of the materials for high temperature gas-cooled reactor.
Sakaguchi, Yoshifumi*; Asaoka, Hidehito; Mitkova, M.*
Journal of Applied Physics, 122(23), p.235105_1 - 235105_12, 2017/12
Times Cited Count:8 Percentile:37.82(Physics, Applied)To, Kentaro; Nakamura, Tatsuya; Sakasai, Kaoru; Yamagishi, Hideshi*
Journal of Instrumentation (Internet), 12(12), p.C12011_1 - C12011_8, 2017/12
Times Cited Count:0 Percentile:0.01(Instruments & Instrumentation)A neutron-detection element using circular cathode bumps was developed for two-dimensional neutron measurement, and an irradiation experiment was performed using a Cf neutron source. The element has triangularly arranged small-sized circular cathode bumps, and the bumps are linked together in the x- and y-directions for the detection of incident neutrons. The element was arranged in the pressure vessel with a fill gas of composition He/(15%)CF at 0.7 MPa. The detector system using bump cathode element exhibited a two-dimensional uniformity with a response of 10.1%. The average intrinsic spatial resolution was 1.89 mm full width at half maximum in the sensitive region, calculated by taking into account the track lengths of the secondary particles.
Kumagai, Yuta; Takano, Masahide; Watanabe, Masayuki
Journal of Nuclear Materials, 497, p.54 - 59, 2017/12
Times Cited Count:13 Percentile:78.05(Materials Science, Multidisciplinary)We studied oxidative dissolution of uranium and zirconium oxide [(U,Zr)O] in aqueous HO solution. The interfacial reaction is essential for anticipating how a (U,Zr)O-based molten fuel may chemically degrade after a severe accident under influence of ionizing radiation. We conducted our experiments with (U,Zr)O powder and quantitated the HO reaction via dissolved U and HO concentrations. The dissolution yield relative to HO consumption was far less for (U,Zr)O compared to that of UO. The reaction kinetics indicates that most of the HO catalytically decomposed to O at the surface of (U,Zr)O. We confirmed the HO catalytic decomposition via O production (quantitative stoichiometric agreement). In addition, post-reaction Raman scattering spectra of the undissolved (U,Zr)O showed no additional peaks (indicating a lack of secondary phase formation). The (U,Zr)O matrix is much more stable than UO against HO-induced oxidative dissolution.
Kamiya, Junichiro; Kinsho, Michikazu; Yamazaki, Yoshio; Yoshimoto, Masahiro; Yanagibashi, Toru*
Journal of the Vacuum Society of Japan, 60(12), p.484 - 489, 2017/12
Multi-turn H charge exchange injection is employed as a beam injection method in the 3-GeV RCS (Rapid cycling synchrotron) at J-PARC (Japan Proton Accelerator Research Complex). In this method, injection H beam is put on the same orbit as already circulating proton (H) beam in a dipole magnetic field due to the opposite curvature of the injected and circulating beams. In the straight section, where the two beams coincide with each other, both beams are passed through a thin foil, which strips two weakly bound electrons off each H ion, forming an intense beam of protons. The thin foil, which is mostly made of carbon, would be the source of the outgassing, especially when its temperature rises due to the beam hitting. Therefore it is important to estimate the amount and components of the outgassing from the charge stripping foil. In this paper, we will report the thermal desorption measurement results for the several foil, which is used as the charge stripping foil in the RCS.
Ogiwara, Norio; Hikichi, Yusuke*; Kamiya, Junichiro; Kinsho, Michikazu; Yoshida, Hajime*; Arai, Kenta*
Journal of the Vacuum Society of Japan, 60(12), p.475 - 480, 2017/12
Okamoto, Yoshihiro; Nagai, Takayuki; Shiwaku, Hideaki; Inose, Takehiko*; Sato, Seiichi*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 16(4), p.180 - 190, 2017/12
X-ray absorption fine structure (XAFS) and imaging XAFS analyses were performed to elucidate chemical state of rhodium in the simulated waste glass. The chemical forms of Rh in the glass were evaluated to be 84% RhO and 16% metal/alloy as the result of linear combination analysis of EXAFS data. According to the imaging XAFS analysis, the chemical form of Rh which was located together with Ru was mainly oxide (RhO). It suggests that stable (Ru,Rh)O solid solution exists in the simulated glass. On the other hand, that of Rh of which distribution did not accord with Ru in the glass was mainly metallic. In the case of metallic Rh in the glass, it tended to become an aggregation form. It can be concluded that the chemical state of Rh was much affected by the existence and distribution of Ru element.
Nishio, Katsuhisa; Chiba, Satoshi*
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(12), p.717 - 721, 2017/12
no abstracts in English
Ishizuka, Chikako*; Usang, M. D.*; Ivanyuk, F. A.*; Maruhn, J. A.*; Nishio, Katsuhisa; Chiba, Satoshi
Physical Review C, 96(6), p.064616_1 - 064616_9, 2017/12
Times Cited Count:59 Percentile:97.55(Physics, Nuclear)Andel, B.*; Andreyev, A. N.; Antalic, S.*; Barzakh, A.*; Bree, N.*; Cocolios, T. E.*; Comas, V. F.*; Diriken, J.*; Elseviers, J.*; Fedorov, D. V.*; et al.
Physical Review C, 96(5), p.054327_1 - 054327_11, 2017/12
Times Cited Count:3 Percentile:27.61(Physics, Nuclear)Shinto, Katsuhiro; Shibata, Takanori*; Wada, Motoi*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.648 - 650, 2017/12
In J-PARC, peak H current of several tens mA is extracted from an ion source driven by a solid-state rf amplifier with the frequency of 2 MHz for production of a cesiated hydrogen plasma. In case of the rf-driven ion source for producing the high-intensity H current, the plasma density in the source chamber is so high that the ion sheath around the beam extraction area can follow the rf oscillation. The H beam current fluctuation as large as approximately 1 mA was observed at the average beam current of 44 mA measured by a Faraday cup installed downstream of the ion source. The beam exhibited some fluctuation to the transverse motion as well. To further clarify this high frequency oscillation of the beam extraction sheath, we propose a measurement system using a time-resolved and highly sensitive emittance monitor in order to observe the real-time beam fluctuation in the phase space.
Harada, Hiroyuki; Yamane, Isao*; Saha, P. K.; Suganuma, Kazuaki; Kinsho, Michikazu; Irie, Yoshiro*; Kato, Shinichi
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.684 - 688, 2017/12
The high-intensity proton accelerator adopts a charge exchange injection scheme, which injects with exchanging from negative Hydrogen ion to proton by using carbon foil. This scheme can realize high intensity proton beam but the uncontrolled beam losses are caused by scattering between beams and the foil. Additionally, the collision may occur the foil beak. Therefore, a new injection scheme for higher intensity is needed as an alternative to the foil. In the J-PARC 3GeV RCS, we newly propose and develop a laser stripping injection scheme. However, it is necessary that laser power is two order higher than latest laser one. To realize this big issue, we develop the laser storage ring, which can provide laser pulse of high repetition rate by recycling one. In this presentation, we will introduce the laser stripping injection scheme and describe the concept of the laser storage ring with high repetition rate and report the current status.
Tamura, Fumihiko; Sugiyama, Yasuyuki*; Yoshii, Masahito*; Omori, Chihiro*; Yamamoto, Masanobu; Shimada, Taihei; Hasegawa, Katsushi*; Hara, Keigo*; Furusawa, Masashi*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.241 - 245, 2017/12
Beam loading compensation in magnetic alloy (MA) cavities is necessary to accelerate high intensity proton beams in the J-PARC 3GeV rapid cycling synchrotron (RCS). Because of its wide frequency response, wake voltages in the cavity by the beam contain multiharmonic components and the beam loading compensation must be multiharmonics. The J-PARC RCS utilize the multiharmonic rf feedforward system for the beam loading compensation. Although the performance of the feedforward is good, we have found some limitations of performance due to the open loop configuration of the feedforward system. For the next generation LLRF control system for the RCS, we consider to employ vector rf control in addition to the feedforward for beam loading compensation. We developed a prototype of the vector rf control. The system details, commissioning methodology, and preliminary beam test results are presented.
Hotchi, Hideaki; Harada, Hiroyuki; Kato, Shinichi; Okabe, Kota; Saha, P. K.; Shobuda, Yoshihiro; Tamura, Fumihiko; Tani, Norio; Watanabe, Yasuhiro; Yoshimoto, Masahiro
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.95 - 99, 2017/12
no abstracts in English
Hayashi, Naoki; Kikuzawa, Nobuhiro; Miura, Akihiko; Futatsukawa, Kenta*; Miyao, Tomoaki*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.540 - 544, 2017/12
The J-PARC linac operation is stable, however, the numbers of interlocked events due to single beam loss monitor (BLMP) is increasing. Recently, the counts is comparable to the number of RFQ trip, and a measure has been required for improvement of the operation efficiency. Thus, every event data has been analyzed and classified into three categories. It is found that there are characteristic signal or pattern of BLMP for every categories. Although the linac BLMP detector is standard, its setting parameters are differ from those of other two synchrotrons in the J-PARC. To optimize time resolution, the input impedance of its pre-amplifier is selected to be 50 and interlock is defined in raw signal height and width not integral signal of BLMP. Some new parameters has been tried to reduce unnecessary interlock.
Saha, P. K.; Harada, Hiroyuki; Yamane, Isao*; Kinsho, Michikazu; Miura, Akihiko; Okabe, Kota; Liu, Y.*; Yoshimoto, Masahiro; Kato, Shinichi; Irie, Yoshiro*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.866 - 870, 2017/12
Okabe, Kota; Yamamoto, Kazami; Kamiya, Junichiro; Takayanagi, Tomohiro; Yamamoto, Masanobu; Yoshimoto, Masahiro; Takeda, Osamu*; Horino, Koki*; Ueno, Tomoaki*; Yanagibashi, Toru*; et al.
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.853 - 857, 2017/12
The most important issue is to reduce the uncontrolled beam loss in the high intensity hadron accelerator such as J-PARC proton accelerators. The J-PARC 3 GeV Synchrotron (RCS) has a collimator system which narrows a high intensity beam in the RCS. After startup of RCS in 2007, the collimator system of the RCS worked well. However, in April 2016, vacuum leakage at the collimator system occurred during the maintenance operation. To investigate a cause of the failure, we took apart iron shields of the collimator reducing exposed dose of operators. As a result of inspection, we succeeded to identify the cause of the vacuum leakage failure. In this presentation, we report the failure investigation of the beam collimator system in the RCS.
Fujirai, Kosuke; Suganuma, Kazuaki; Yamazaki, Yoshio
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.874 - 876, 2017/12
The J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid Cycling Synchrotron) has many devices such as Radio-Frequency components, electromagnets and power supplies. These devices use 17MW of electricity during operation, most of which is consumed as thermal energy. Therefore, cooling water equipment is indispensable for the operation of the accelerator and its stability affects the operation rate of the accelerator. Due to resent operation experience, the bearing unit of the cooling tower fan, which is also an important part of the cooling water equipment, broke down. This accident leads to the suspension of the J-PARC operation. In order to investigate the cause of the failure, we tried to measure vibration for the defective bearing and the bearing unit were cut and observed damaged surface. As a result of the vibration measurement, it was found that vibration frequency depends on the presence or absence of scratches on the bearing. We found surface of the outer ring had scratches called flaking.
Takahashi, Hiroki; Sawabe, Yuki; Watanabe, Kazuhiko*; Kawase, Masato*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1151 - 1154, 2017/12
The amount of monitor value tends to increase, because of the increase of accelerator components, or in order to realize the safety and the stable operation. Then, an enormous volume of operation data increases the possibility of occurrence of erroneous operation such as overlooking of monitor value and etc. Then, we started to develop a system to supervise the state of the accelerator and to inform operators of abnormality early. As an initial system, we developed a system to supervise the status of Linac DTQ power supplies and etc. In this initial system, first, the function was created to make the normal range (upper and lower limit values) with reference to the current setting value. Next, the function to inform the alarm condition when the monitor value becomes outside of the normal range was realized. This function is an important function in the initial system. By this realization, we obtained the prospect of development of supervision and alarm system.
Sawabe, Yuki*; Takahashi, Hiroki; Ito, Yuichi*; Kawase, Masato*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1133 - 1136, 2017/12
In the timing system of J-PARC LINAC/RCS, the ring type Reflective Memory (RFM) network is adopted for data transfer. In June 2016, a data transfer failure occurred due to communication error on the RFM network, and it took a long time to recover. From this experience, we have created the environment to monitor of the RFM network status, and we duplicated the computer which manages the data transfer on the RFM network. In Addition, we have also created the syslog function as an environment to monitor each RFM even if data transfer failure occurs on the RFM network. After these improvements, a trouble occurred in the timing system VME. At the same time, the target device was immediately identified by these functions, and the timing system could be recovered quickly. In this paper, the details of improvement for stable operation in the timing system of J-PARC LINAC / RCS are presented.
Suganuma, Kazuaki; Hiroki, Fumio; Ito, Takashi; Yamazaki, Yoshio
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.871 - 873, 2017/12
J-PARC LINAC has a problem that the amount of the flowing water is reduced. It spends such time from alarm to the restoration that it is desirable to take measures. So we have to solve this problem. We tried to focus again on the related water level fluctuation in the storage tank of cooling water equipment and the flow rate fluctuation all of the cooling water that has observed in cooling water equipment named RI4 from RFQ to SDTL of the LINAC. At the same time, we check new information of the operating data. We have hypothesized about the cause of fluctuation of the whole flow rate. That can be deterioration of water quality and lacking of performance of circulation pumps. That can be deterioration of water quality and lacking of performance of circulation pumps.
Hamamoto, Takafumi*; Shibutani, Sanae*; Ishida, Keisuke*; Fujisaki, Kiyoshi*; Yamada, Motoyuki*; Tachi, Yukio
Proceedings of 6th East Asia Forum on Radwaste Management Conference (EAFORM 2017) (Internet), 6 Pages, 2017/12
NUMO has developed a generic safety case to demonstrate the feasibility and safety of geological disposal of HLW and TRU in Japan and to provide a basic structure for the safety case which will be applicable to any potential site. In this safety case, the safety assessment was carried out for the repositories tailored to site descriptive models developed for three representative rock groups (plutonic, Neogene sedimentary and Pre-Neogene sedimentary rocks). Radionuclide migration parameters in rocks, i.e. distribution coefficients (Kds) and effective diffusion coefficients (Des), were derived to allow safety analysis for a range of scenarios. In this generic stage, the values of these parameter were given as the statistical values derived from laboratory data for certain rock types. The data were extracted from the latest database, with interpretation based on radionuclide speciation derived from relevant groundwater thermodynamic modelings.
Shobuda, Yoshihiro; Chin, Y. H.*
Progress of Theoretical and Experimental Physics (Internet), 2017(12), p.123G01_1 - 123G01_22, 2017/12
Times Cited Count:9 Percentile:56.98(Physics, Multidisciplinary)no abstracts in English
Hirade, Tetsuya
Acta Physica Polonica A, 132(5), p.1470 - 1472, 2017/11
Times Cited Count:3 Percentile:29.1(Physics, Multidisciplinary)The positron annihilation lifetime measurements in RTILs showed very strange results. Finally, positron annihilation age-momentum correlation (AMOC) measurements indicated that it was caused by slow bubble formation in RTILs. Then I discovered the oscillation of o-Ps annihilation rates in room temperature ionic liquids (RTILs) which indicated, probably, the oscillation of the Ps bubble. Stepanov et al. calculated change of the bubble size in many liquids and the oscillation of the bubble was not expected except for a liquid He. It means that the structure of RTILs in nanometer scale is very different from usual liquids. Moreover, o-Ps pick-off annihilation rates seems to be too small for the macroscopic surface tension of RTILs. I am going to discuss what you can study by the positron annihilation methods for the structure of RTILs in nanometer scale.
Yomogida, Takumi; Esaka, Fumitaka; Magara, Masaaki
Analytical Methods, 9(44), p.6261 - 6266, 2017/11
Times Cited Count:9 Percentile:55.65(Chemistry, Analytical)A combination of micro-sampling, micro-Raman spectroscopy (MRS), and secondary ion mass spectrometry (SIMS) was applied to the characterization of individual uranium particles. Reference particles with UO (NBL CRM U010) and UO were identified by scanning electron microscopy combined with energy dispersive X-ray detection (SEM-EDX) and transferred onto grassy carbon substrates by micro-sampling. The crystalline phases of the reference particles with diameters ranging from 1 m to 5 m were determined non-destructively by using MRS thanks to the optimization of laser power at the measurement. Isotope ratios were also determined with SIMS after the MRS analysis and were consistent with values in the literature. These results indicate that chemical forms and isotope ratios of individual uranium particles as small as 1 m can be analyzed efficiently by using the proposed method.
Saito, Kyoichi*; Asai, Shiho
Bunseki Kagaku, 66(11), p.771 - 782, 2017/11
Times Cited Count:1 Percentile:3.41(Chemistry, Analytical)Recovery and purification of rare metals, which are essential ingredients for highly functional materials, generally comes with operational difficulty. In this study, we have developed polymer adsorbents specially designed for highly-efficient adsorption of rare metal ions and exhibited their practical adsorption performances. Radiation-induced graft polymerization, one of the effective modification techniques for polymers, was employed for preparing the proposed adsorbents. Among such adsorbents, a 6-nylon fiber with nucleic-acid base, adenine, on the surface of the fiber demonstrated specific adsorption of ruthenium and palladium ions. In addition, a 6-nylon fiber with an extractant HDEHP (bis (2-ethylhexyl) phophoric acid) that has high affinity for lanthanides, achieved higher separation speed than a commercially available HDEHP-impregnated resin.
Yuguchi, Takashi*; Sueoka, Shigeru; Iwano, Hideki*; Danhara, Toru*; Ishibashi, Masayuki; Sasao, Eiji; Nishiyama, Tadao*
Island Arc, 26(6), p.e12219_1 - e12219_15, 2017/11
Times Cited Count:11 Percentile:39.42(Geosciences, Multidisciplinary)The spatial distribution of AFT age in the granitic body is a favorable key to reveal a cooling behavior of the whole pluton. The cooling behavior is attributable to the regional exhumation of the Toki granite related to the regional denudation of the Tono district. Combination of the AERs and AFT inverse model applying to the granite is a powerful procedure for evaluating the cooling and exhumation history of the granitic pluton and thus denudation history of the tectonic region that surrounded the rock body.
Jentschel, M.*; Blanc, A.*; de France, G.*; Kster, U.*; Leoni, S.*; Mutti, P.*; Simpson, G.*; Soldner, T.*; Ur, C.*; Urban, W.*; et al.
Journal of Instrumentation (Internet), 12(11), p.P11003_1 - P11003_33, 2017/11
Times Cited Count:38 Percentile:84.92(Instruments & Instrumentation)Fujita, Hiroki; Maehara, Yushi; Nagaoka, Mika; Koarashi, Jun
KEK Proceedings 2017-6, p.35 - 39, 2017/11
no abstracts in English
Nagaoka, Mika; Matsubara, Natsumi; Fujita, Hiroki; Nakano, Masanao
KEK Proceedings 2017-6, p.212 - 217, 2017/11
no abstracts in English
Watanabe, Takayoshi; Oyama, Takuya; Ishii, Yasuo; Niizato, Tadafumi; Abe, Hironobu; Mitachi, Katsuaki; Sasaki, Yoshito
KEK Proceedings 2017-6, p.122 - 126, 2017/11
no abstracts in English
Nakanishi, Takahiro; Oyama, Takuya; Hagiwara, Hiroki
KEK Proceedings 2017-6, p.107 - 111, 2017/11
At riverbanks in six rivers (Odaka, Ukedo, Takase, Kuma, Tomioka and Kido rivers) of eastern Fukushima, dose rate distribution in the cross section had been observed from January 2013 to December 2016. Dose rates in the flood plain which were flooded periodically were different from the surroundings. In rivers without reservoirs (Odaka, Takase and Kuma rivers), dose rates in the flood plain were affected by average radiocesium inventory in the whole catchments. By contrast, in rivers with reservoirs (Ukedo, Tomioka and Kido rivers), dose rates in the flood plain were affected by those in the downstream area of reservoirs and the erosion effect.
Zheng, X.; Tamaki, Hitoshi; Shiotsu, Hiroyuki; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 11 Pages, 2017/11
Tamaki, Hitoshi; Yoshida, Kazuo; Abe, Hitoshi; Sugiyama, Tomoyuki; Maruyama, Yu
Proceedings of Asian Symposium on Risk Assessment and Management 2017 (ASRAM 2017) (USB Flash Drive), 9 Pages, 2017/11
An accident of evaporation to dryness caused by boiling of high level radioactive liquid waste (HLLW) is postulated as one of severe accidents caused by the loss of cooling function at the fuel reprocessing plant. This accident can be divided into early boiling stage, late boiling stage and dry-out stage by characteristics of accident evolution. It is important to estimate the amount of fission product (FP) transport between the liquid and gas phases, and the amount of FP deposition on the walls in each stage in order to estimate the release amount of FP to the environment. Various research activities have been carried out for this issue. This paper reviews these activities and presents the recent activities at JAEA for development of simulation code for this type of accident.
Harjo, S.; Kawasaki, Takuro; Morooka, Satoshi
Advanced Experimental Mechanics, 2, p.112 - 117, 2017/10
Yoshikawa, Hideki
Enerugi Rebyu, 37(10), p.13 - 14, 2017/10
We introduce the R&D activities of Japan Atomic Energy Agency immediately after the accident at Fukushima Daiichi Nuclear Power Station and some facilities established in Fukushima Prefecture.
Soejima, Goro; Iwai, Hiroki; Kadowaki, Haruhiko; Nakamura, Yasuyuki; Tsuzuki, Satoshi*; Yasunaga, Kazushi*; Nakata, Yoshinori*; Kume, Kyo*
Heisei-28-Nendo Koeki Zaidan Hojin Wakasawan Enerugi Kenkyu Senta kenkyu Nempo, 19, P. 9, 2017/10
no abstracts in English
Lam, Do Van*; Suematsu, Hisayuki*; Ogawa, Toru
Journal of the American Ceramic Society, 100(10), p.4884 - 4892, 2017/10
Times Cited Count:2 Percentile:10.4(Materials Science, Ceramics)Nanoparticles of ZrN, ZrO and ZrN, '-ZrON were synthesized by pulsed wire discharge. Morphology and phase analyses were carried out by X-ray diffraction and field-emission transmission electron microscopy (FE-TEM). By bright field image observation, electron energy loss spectroscopy (EELS) and selected area electron diffraction (SAD) analyses, those nanoparticles were separately characterized.
Onuma, Yuichi; Matsuo, Mamoru*; Maekawa, Sadamichi
Physical Review B, 96(13), p.134412_1 - 134412_4, 2017/10
Times Cited Count:38 Percentile:83.36(Materials Science, Multidisciplinary)A microscopic theory of the spin Peltier effect in a bilayer structure comprising a paramagnetic metal (PM) and a ferromagnetic insulator (FI) based on the nonequilibrium Green's function method is presented. Spin current and heat current driven by temperature gradient and spin accumulation are formulated as functions of spin susceptibilities in the PM and the FI, and are summarized by Onsager's reciprocal relations. By using the current formulas, we estimate heat generation and absorption at the interface driven by the heat-current injection mediated by spins from PM into FI.
Wilson, G. L.*; Takeyama, Mirei*; Andreyev, A. N.; Andel, B.*; Antalic, S.*; Catford, W. N.*; Ghys, L.*; Haba, Hiromitsu*; Heberger, F. P.*; Huang, M.*; et al.
Physical Review C, 96(4), p.044315_1 - 044315_7, 2017/10
Times Cited Count:6 Percentile:47.01(Physics, Nuclear)Miyahara, Kaname
Transactions of the American Nuclear Society, 117(1), p.51 - 52, 2017/10
This presentation highlights JAEA's challenges for contributing to recovering the previous life of residents and the development of resilient communities in Fukushima Prefecture based on considering needs of local people on the environmental restoration categorized by the state of evacuation orders and the lifting of such orders.
Yoneda, Yasuhiro; Taniguchi, Hiroki*; Fu, D.*
Ferroelectrics, 513(1), p.1 - 6, 2017/09
Times Cited Count:7 Percentile:35.49(Materials Science, Multidisciplinary)An EXAFS study of lead magnesium niobate was performed at the Nb K edge and at the Pb L3 edge at 300 K. Two Nb-O bond lengths of 1.91 and 2.10 are observed and there is no significant modification of the local environment of the Nb atoms compared with NaNbO and AgNbO. The weak Pb L3 EXAFS signal indicated a strong static disorder, which can be extracted by PDF analysis.
Nishio, Katsuhisa
Genshikaku Kenkyu, 62(1), p.89 - 94, 2017/09
no abstracts in English
Jungclaus, A.*; Grawe, H.*; Nishimura, Shunji*; Doornenbal, P.*; Lorusso, G.*; Simpson, G. S.*; Sderstrm, P.-A.*; Sumikama, Toshiyuki*; Taprogge, J.*; Xu, Z. Y.*; et al.
Physics Letters B, 772, p.483 - 488, 2017/09
Times Cited Count:8 Percentile:55.37(Astronomy & Astrophysics)Adare, A.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 497 of others*
Physical Review C, 96(2), p.024907_1 - 024907_19, 2017/08
Times Cited Count:11 Percentile:65.8(Physics, Nuclear)Julius, T.*; Tanida, Kiyoshi; Belle Collaboration*; 184 of others*
Physical Review D, 96(3), p.032007_1 - 032007_8, 2017/08
Times Cited Count:11 Percentile:49.91(Astronomy & Astrophysics)Ise, Kotaro; Sasaki, Yoshito; Amano, Yuki; Iwatsuki, Teruki; Nanjo, Isao*; Asano, Takahiro*; Yoshikawa, Hideki
Geomicrobiology Journal, 34(6), p.489 - 499, 2017/07
Times Cited Count:4 Percentile:14.09(Environmental Sciences)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.
Saito, Yuji; Yasui, Akira*; Fuchimoto, Hiroto*; Nakatani, Yasuhiro*; Fujiwara, Hidenori*; Imada, Shin*; Narumi, Yasuo*; Kindo, Koichi*; Takahashi, Minoru*; Ebihara, Takao*; et al.
Physical Review B, 96(3), p.035151_1 - 035151_5, 2017/07
Times Cited Count:3 Percentile:17.1(Materials Science, Multidisciplinary)We revisit the delocalized character of the 4 states of CeFe in the ferromagnetically ordered phase by X-ray magnetic circular dichroism (XMCD) in X-ray absorption spectroscopy (XAS) with improved data quality using single crystals. Surprisingly, the Ce XMCD spectral shape changes significantly as a function of temperature and applied magnetic field, with no concomitant changes in the spectral shape of the Ce XAS as well as the Fe XAS and XMCD. This unusual behavior is characterized by the states in a 4 configuration mixed into the ground state. Such extreme sensitivity of the Ce 4 states to the external perturbations can be related to the magnetic instability toward an antiferromagnetic phase in CeFe. Our experimental data presented here provide valuable insights into the underlying physics in strongly-hybridized ferromagnetic Ce compounds.
Daimon, Shunsuke*; Uchida, Kenichi*; Iguchi, Ryo*; Hioki, Tomosato*; Saito, Eiji
Physical Review B, 96(2), p.024424_1 - 024424_12, 2017/07
Times Cited Count:35 Percentile:82.2(Materials Science, Multidisciplinary)Honda, Ryotaro*; Hasegawa, Shoichi; Hayakawa, Shuhei; Hosomi, Kenji; Ichikawa, Yudai; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki; Sato, Susumu; Sugimura, Hitoshi; et al.
Physical Review C, 96(1), p.014005_1 - 014005_23, 2017/07
Times Cited Count:14 Percentile:73.79(Physics, Nuclear)Soejima, Goro; Iwai, Hiroki; Nakamura, Yasuyuki; Hayashi, Hirokazu; Kadowaki, Haruhiko; Mizui, Hiroyuki; Sano, Kazuya
Proceedings of 25th International Conference on Nuclear Engineering (ICONE-25) (CD-ROM), 5 Pages, 2017/07
no abstracts in English
Sako, Takashi*; Tanida, Kiyoshi; 21 of others*
EPJ Web of Conferences, 145, p.10005_1 - 10005_4, 2017/06
Kikkawa, Takashi*; Suzuki, Motohiro*; Okabayashi, Jun*; Uchida, Kenichi*; Kikuchi, Daisuke*; Qiu, Z.*; Saito, Eiji
Physical Review B, 95(21), p.214416_1 - 214416_7, 2017/06
Times Cited Count:16 Percentile:60.44(Materials Science, Multidisciplinary)Aidala, C.*; Hasegawa, Shoichi; Imai, Kenichi; Nagamiya, Shoji; Sako, Hiroyuki; Sato, Susumu; Tanida, Kiyoshi; PHENIX Collaboration*; 431 of others*
Physical Review D, 95(11), p.112001_1 - 112001_15, 2017/06
Times Cited Count:17 Percentile:63.64(Astronomy & Astrophysics)Chilikin, K.*; Tanida, Kiyoshi; Belle Collaboration*; 167 of others*
Physical Review D, 95(11), p.112003_1 - 112003_17, 2017/06
Times Cited Count:47 Percentile:89.68(Astronomy & Astrophysics)Aizawa, Kosuke; Chikazawa, Yoshitaka; Ara, Kuniaki; Yui, Masahiro*; Uemoto, Yohei*; Kurokawa, Masaaki*; Hiramatsu, Takashi*
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 9 Pages, 2017/06
Inspection in opaque liquid metal coolant is one of important issues for sodium-cooled fast reactors. To facilitate operations and maintenance activities, various under sodium viewers (USVs), including horizontal USVs for obstacle detection for a long distance and imaging USVs for a short and middle distance imaging, have been developed in several research institutes and countries. In this study, an imaging USV for a middle distance, approximately 1 m, has been developed. The USV in this study adopts an optical receiving system which measures the vibration displacement of diaphragm by using a laser as a receiving sensor. This study mainly focuses on the sensitivity improvement for a transmission sensor and the receiving sensor. In addition, an imaging experiment in the water was conducted using the new transmission sensor and receiving sensor. The experimental results showed that the newly developed USV sensors can make higher resolution images of a target than the previous sensors.
Ramos, R.*; Kikkawa, Takashi*; Anadn, A.*; Lucas, I.*; Uchida, Kenichi*; Algarabel, P. A.*; Morelln, L.*; Aguirre, M. H.*; Saito, Eiji; Ibarra, M. R.*
AIP Advances (Internet), 7(5), p.055915_1 - 055915_7, 2017/05
Times Cited Count:19 Percentile:65.79(Nanoscience & Nanotechnology)Prasanth, K.*; Tanida, Kiyoshi; Belle Collaboration*; 195 of others*
Physical Review D, 95(9), p.091101_1 - 091101_8, 2017/05
Times Cited Count:8 Percentile:43.8(Astronomy & Astrophysics)Sekihara, Takayasu; Hyodo, Tetsuo*; Jido, Daisuke*; Yamagata-Sekihara, Junko*; Yasui, Shigehiro*
Proceedings of Science (Internet), 281, p.289_1 - 289_8, 2017/05
Fujimura, Koji*; Itooka, Satoshi*; Oki, Shigeo; Takeda, Toshikazu*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 6 Pages, 2017/04
Oki, Shigeo; Maruyama, Shuhei; Chikazawa, Yoshitaka; Ohtaki, Akira; Kubo, Shigenobu; Hibi, Koki*; Kan, Taro*
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 9 Pages, 2017/04
Kan, Taro*; Ogura, Masashi*; Hibi, Koki*; Oki, Shigeo; Maeda, Seiichiro; Maruyama, Shuhei; Ohgama, Kazuya
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04
Amano, Yuki; Iwatsuki, Teruki; Naganuma, Takeshi*
Geomicrobiology Journal, 34(9), p.769 - 783, 2017/03
Times Cited Count:6 Percentile:21.84(Environmental Sciences)Two biofilm samples were collected from anaerobic groundwater in a borehole drilled in the Tono area, Japan, to understand the effects of biofilms on the migration behavior of heavy metals in subsurface environments. Biofilms grown on in groundwater of sedimentary rocks and granite groundwater were characterized geochemically and microbiologically, and their heavy metal sorption capability was examined. Clone library analysis was constructed from the biofilms to evaluate microbial community composition. From the results of 16S rRNA gene analyses using clone libraries, it was found that these microbial community compositions in the biofilms were clearly different from the composition of unattached, planktonic microorganisms in the groundwater samples. Furthermore, the microbial community structures generated in each biofilm were different, depending on the groundwater type. It is shown that the community structure of biofilms lacked diversity in groundwater types obtained from sedimentary and granitic rocks. These results indicate that biofilms are formed in natural subsurface environments with site-specific community compositions. High amounts of heavy metals such as Fe, Ni, Cu, Zn, As, Cd, Pb, Th, and U accumulated in the biofilms, and their sorption properties varied in each elements. These results provide important insight on heavy metal sorption capability by biofilms.
Hernsdorf, A. W.*; Amano, Yuki; Miyakawa, Kazuya; Ise, Kotaro; Suzuki, Yohei*; Anantharaman, K.*; Probst, A. J.*; Burstein, David*; Thomas, B. C.*; Banfield, J. F.*
ISME Journal, 11, p.1915 - 1929, 2017/03
Times Cited Count:89 Percentile:95.92(Ecology)To evaluate the potential for interactions between microbial communities and disposal systems, we explored the structure and metabolic function of a sediment-hosted subsurface ecosystem associated with Horonobe Underground Research Center, Hokkaido, Japan. Overall, the ecosystem is enriched in organisms from diverse lineages and many are from phyla that lack isolated representatives. The majority of organisms can metabolize H, often via oxidative [NiFe] hydrogenases or electron-bifurcating [FeFe] hydrogenases that enable ferredoxin-based pathways, including the ion motive Rnf complex. Many organisms implicated in H metabolism are also predicted to catalyze carbon, nitrogen, iron, and sulfur transformations. Notably, iron-based metabolism was predicted in a bacterial lineage where this function has not been predicted previously and in an ANME-2d archaeaon that is implicated in methane oxidation. We infer an ecological model that links microorganisms to sediment-derived resources and predict potential impacts of microbial activity on H accumulation and radionuclide migration.