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Kusano, Kanya*; Ichimoto, Kiyoshi*; Ishii, Mamoru*; Miyoshi, Yoshizumi*; Yoden, Shigeo*; Akiyoshi, Hideharu*; Asai, Ayumi*; Ebihara, Yusuke*; Fujiwara, Hitoshi*; Goto, Tadanori*; et al.
Earth, Planets and Space (Internet), 73(1), p.159_1 - 159_29, 2021/12
Times Cited Count:6 Percentile:52.8(Geosciences, Multidisciplinary)The PSTEP is a nationwide research collaboration in Japan and was conducted from April 2015 to March 2020, supported by a Grant-in-Aid for Scientific Research on Innovative Areas from the Ministry of Education, Culture, Sports, Science and Technology of Japan. It has made a significant progress in space weather research and operational forecasts, publishing over 500 refereed journal papers and organizing four international symposiums, various workshops and seminars, and summer school for graduate students at Rikubetsu in 2017. This paper is a summary report of the PSTEP and describes the major research achievements it produced.
Noma, Yuichiro*; Kotegawa, Hisashi*; Kubo, Tetsuro*; To, Hideki*; Harima, Hisatomo*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*; Ito, Kohei*; Nakamura, Ai*; et al.
Journal of the Physical Society of Japan, 90(7), p.073707_1 - 073707_5, 2021/07
Times Cited Count:0 Percentile:0(Physics, Multidisciplinary)Marufuji, Takato; Sato, Takumi; Ito, Hideaki; Suzuki, Hisashi; Fujishima, Tadatsune; Nakano, Tomoyuki
JAEA-Technology 2019-006, 22 Pages, 2019/05
Radioactive contamination incident occurred at Plutonium Fuel Research Facility (PFRF) in Oarai Research and Development Institute, Japan Atomic Energy Agency on June 6, 2017. During inspection work of storage container containing nuclear fuel materials, the PVC bag packaging in the storage container ruptured when a worker opened the lid in the hood, and a part of contents was spattered over the room. The cause of the increase of internal pressure of the storage container was gas generation by alpha radiolysis of the epoxy resin mixed with nuclear fuel materials. Opening inspection of about 70 similar containers stored in PFRF has been planned to confirm the condition of the contents and to stabilize the stored materials containing organic compounds. For safe and reliable open inspection of the storage containers with high internal pressure in the glove box, it is necessary to develop a pressure-resistant chamber in which the storage containers are opened and the contents are inspected under gastight condition. This report summarizes the concerns and countermeasures of the chamber design and the design results of the chamber.
Katsuta, Nagayoshi*; Ikeda, Hisashi*; Shibata, Kenji*; Kokubu, Yoko; Murakami, Takuma*; Tani, Yukinori*; Takano, Masao*; Nakamura, Toshio*; Tanaka, Atsushi*; Naito, Sayuri*; et al.
Global and Planetary Change, 164, p.11 - 26, 2018/05
Times Cited Count:8 Percentile:44.36(Geography, Physical)Paleoenvironmental and paleoclimate changes in Siberia were reconstructed by continuous, high-resolution records of chemical compositions from a sediment core retrieved from the Buguldeika Saddle, Lake Baikal, dating back to the last 33 cal. ka BP. The Holocene climate followed by a shift at ca. 6.5 cal. ka BP toward warm and dry, suggesting that the climate system transition from the glacial to interglacial state occurred. In the last glacial period, the deposition of carbonate mud from the Primorsky Range was associated with Heinrich events (H3 and H1) and the Selenga River inflow was caused by meltwater of mountain glaciers in the Khamar-Daban Range. The anoxic bottom-water during Allerod-Younger Dryas was probably a result of weakened ventilation associated with reduced Selenga River inflow and microbial decomposition of organic matters from the Primorsky Range. The rapid decline in precipitation during the early Holocene may have been a response to the 8.2 ka cooling event.
Noma, Yuichiro*; Kotegawa, Hisashi*; Kubo, Tetsuro*; To, Hideki*; Harima, Hisatomo*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika*; Ito, Kohei*; Haller, E. E.*; et al.
Journal of the Physical Society of Japan, 87(3), p.033704_1 - 033704_5, 2018/03
Times Cited Count:4 Percentile:36.2(Physics, Multidisciplinary)Takamizawa, Hisashi; Ito, Hiroto; Nishiyama, Yutaka
Journal of Nuclear Materials, 479, p.533 - 541, 2016/10
Times Cited Count:5 Percentile:49.65(Materials Science, Multidisciplinary)To understand neutron irradiation embrittlement in high fluence regions, statistical analysis using the Bayesian nonparametric (BNP) method was performed for the Japanese surveillance and material test reactor irradiation database. The BNP method is essentially expressed as an infinite summation of normal distributions, with input data being subdivided into clusters with identical statistical parameters (such as mean and standard deviation) for each cluster to estimate shifts in ductile-to-brittle transition temperature (DBTT). Clusters typically depend on chemical compositions, irradiation conditions, and the irradiation embrittlement. Specific variables contributing to the irradiation embrittlement include the content of Cu, Ni, P, Si, and Mn in the pressure vessel, neutron flux, neutron fluence, and irradiation temperatures. It was found through numerous examinations that the measured shifts of DBTT correlated well with calculated ones. Data associated with the same materials were subdivided into the same clusters even if neutron fluences were significantly disparate among the results. This indicates that slowly developing or late-onset embrittlement mechanisms were not evident in the present study.
Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
Saito, Takumi; Makino, Hisashi*; Tanaka, Satoru*
Journal of Environmental Radioactivity, 138, p.11 - 18, 2014/12
Times Cited Count:64 Percentile:86.61(Environmental Sciences)Radioactive cesium was predominantly found in the extract obtained by strong-acid dissolution and the extraction residue and was more concentrated in silt and clay grains. X-ray diffraction analyses revealed that micaceous minerals as well as kaolin minerals were predominantly dissolved by the strong-acid treatment. Correlation between the fraction of Cs and the content of micaceous minerals in different grain-size fractions of soil minerals suggests that micaceous minerals are responsible for the fixation of Cs in the soils. The isotopic ratio of Cs and Cs in the extract by strong-acid dissolution was more than three times smaller than those in the extracts by water, ion exchange, and reductive dissolution. This indicates that the distribution of Cs was not in the steady state in 2 y after the accident due to relatively slow fixation by the soil clay minerals.
Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; Ida, Mizuho*; Ito, Yuzuru; Niitsuma, Shigeto; Edao, Yuki; et al.
Fusion Science and Technology, 66(1), p.46 - 56, 2014/07
Times Cited Count:4 Percentile:31.13(Nuclear Science & Technology)Yamagishi, Isao; Nagaishi, Ryuji; Kato, Chiaki; Morita, Keisuke; Terada, Atsuhiko; Kamiji, Yu; Hino, Ryutaro; Sato, Hiroyuki; Nishihara, Kenji; Tsubata, Yasuhiro; et al.
Journal of Nuclear Science and Technology, 51(7-8), p.1044 - 1053, 2014/07
Times Cited Count:16 Percentile:76.9(Nuclear Science & Technology)For safe storage of zeolite wastes generated by treatment of radioactive saline water at the Fukushima Daiichi Nuclear Power Station, properties of the Herschelite adsorbent were studied and its adsorption vessel was evaluated for hydrogen production and corrosion. Hydrogen production depends on its water level and dissolved species because hydrogen is oxidized by radicals in water. It is possible to evaluate hydrogen production rate in Herschelite submerged in seawater or pure water by taking into account of the depth effect of the water. The reference vessel of decay heat 504 W with or without residual pure water was evaluated for the hydrogen concentration by thermal hydraulic analysis using obtained fundamental properties. Maximum hydrogen concentration was below the lower explosive limit (4 %). The steady-state corrosion potential of a stainless steel 316L increased with absorbed dose rate but its increase was repressed by the presence of Herschelite. At 750 Gy/h and 60C which were values evaluated at the bottom of the vessel of 504 W, the localized corrosion of SUS316L contacted with Herschelite would not immediately occur under 20,000 ppm of Cl concentration.
Wakai, Eiichi; Kondo, Hiroo; Sugimoto, Masayoshi; Fukada, Satoshi*; Yagi, Juro*; Ida, Mizuho; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(12), p.691 - 705, 2012/12
no abstracts in English
Shimo, Michito*; Kumamoto, So*; Ito, Akira*; Karasaki, Kenji*; Sawada, Atsushi; Oda, Yoshihiro; Sato, Hisashi
JAEA-Research 2010-040, 57 Pages, 2010/11
In safety analysis of geological disposal of the high-level nuclear waste, it is important to evaluate appropriately the mass transport characteristics of the bedrock as the natural barrier. Especially, it has been found that the porosity of the rock matrix is high and fractured zones are developing and therefore the mass transport characteristics will be the mixture of those for porous media and the fractured media. In this work, we conducted, (1) a study on the method to mine out the rock block sample of tens of-centimeter to maximum 1 m scale, (2) a study on a method of the tracer test using a rock block sample and a series of scoping analysis. We also examined the uncertainty associated the hydrogeological model using a method combining a forward and inverse analysis, based on the various type of data sets obtained at Horonobe site, such as the temperature distribution and hydraulic head and salinity distribution.
Shimo, Michito*; Kumamoto, So*; Ito, Akira*; Karasaki, Kenji*; Sawada, Atsushi; Oda, Yoshihiro; Sato, Hisashi
JAEA-Research 2009-060, 70 Pages, 2010/03
It is important for safety assessment of HLW geological disposal to evaluate groundwater flow and mass transport in deep underground appropriately. Though it is considered that the mass transport in sedimentary rock occurs in pores between grains mainly, fractures of sedimentary rock can be main paths. In this study the following three tasks were carried out: (1) laboratory hydraulic and tracer experiments using the rock cores of Wakkanai formation, (2) a study on the tracer test and sampling technique for the larger scale, (3) a study on the reduction technique of uncertainty of the hydrogeological models using data from surface-based investigation. On the block scale tracer test technique, the sampling technique using wire saw and tracer test technique using block samples were suggested. As for the reduction technique of uncertainty of the hydrogeological model, availability of the information other than pressure data, such as the temperature and salinity and all, were presented.
Tobita, Kenji; Nishio, Satoshi; Enoeda, Mikio; Kawashima, Hisato; Kurita, Genichi; Tanigawa, Hiroyasu; Nakamura, Hirofumi; Honda, Mitsuru; Saito, Ai*; Sato, Satoshi; et al.
Nuclear Fusion, 49(7), p.075029_1 - 075029_10, 2009/07
Times Cited Count:135 Percentile:97.73(Physics, Fluids & Plasmas)Recent design study on SlimCS focused mainly on the torus configuration including blanket, divertor, materials and maintenance scheme. For vertical stability of elongated plasma and high beta access, a sector-wide conducting shell is arranged in between replaceable and permanent blanket. The reactor adopts pressurized-water-cooled solid breeding blanket. Compared with the previous advanced concept with supercritical water, the design options satisfying tritium self-sufficiency are relatively scarce. Considered divertor technology and materials, an allowable heat load to the divertor plate should be 8 MW/m or lower, which can be a critical constraint for determining a handling power of DEMO (a combination of alpha heating power and external input power for current drive).
Tanigawa, Hiroyasu; Hirose, Takanori; Shiba, Kiyoyuki; Kasada, Ryuta*; Wakai, Eiichi; Serizawa, Hisashi*; Kawahito, Yosuke*; Jitsukawa, Shiro; Kimura, Akihiko*; Kono, Yutaka*; et al.
Fusion Engineering and Design, 83(10-12), p.1471 - 1476, 2008/12
Times Cited Count:78 Percentile:97.75(Nuclear Science & Technology)Reduced activation ferritic/martensitic steels (RAFMs) are recognized as the primary candidate structural materials for fusion blanket systems. F82H, which were developed and studied in Japan, was designed with an emphasis on high temperature properties and weldability. The database on F82H properties is currently the most extensive available among the existing RAFMs. The objective of this paper is to review the R&D status of F82H and to identify the key technical issues for the fabrication of an ITER Test Blanket Module (TBM) suggested by recent achievements in Japan.
Sakanaka, Shogo*; Ago, Tomonori*; Enomoto, Atsushi*; Fukuda, Shigeki*; Furukawa, Kazuro*; Furuya, Takaaki*; Haga, Kaiichi*; Harada, Kentaro*; Hiramatsu, Shigenori*; Honda, Toru*; et al.
Proceedings of 11th European Particle Accelerator Conference (EPAC '08) (CD-ROM), p.205 - 207, 2008/06
Future synchrotron light sources based on the energy-recovery linacs (ERLs) are expected to be capable of producing super-brilliant and/or ultra-short pulses of synchrotron radiation. Our Japanese collaboration team is making efforts for realizing an ERL-based hard X-ray source. We report recent progress in our R&D efforts.
Nakano, Takashi*; Arakawa, Kazuo; Sakurai, Hideyuki*; Hasegawa, Masatoshi*; Yuasa, Kazuhisa*; Saito, Etsuko*; Takagi, Hitoshi*; Nagamine, Takeaki*; Kusakabe, Takahiko*; Takada, Hisashi*; et al.
International Journal of PIXE, 16(1&2), p.69 - 76, 2006/00
A new program was started out to create a new medical scientific field, which is consisting of radiation oncology and nuclear medicine, utilizing the advanced accelerator and ion beam technology. An in-air micro-PIXE analyzer system, which is among the most important technical basis of the program, was upgraded to improve accuracy of elemental mapping for samples having thickness variation in a scope of microbeam scanning. In the program, on the other hand, in order to approach important bio-medical problems on cancer, intracellular dynamics of the trace elements according to mechanism of development of diseases were studied using this system. This paper outlines this program and shows the system upgraded, and results of preliminary studied about the problems.
Harada, Atsuyuki*; Kawasaki, Shinji*; Kotegawa, Hisashi*; Kitaoka, Yoshio*; Haga, Yoshinori; Yamamoto, Etsuji; Onuki, Yoshichika; Ito, Kohei*; Haller, E. E.*; Harima, Hisatomo*
Journal of the Physical Society of Japan, 74(10), p.2675 - 2678, 2005/10
Times Cited Count:20 Percentile:68.7(Physics, Multidisciplinary)no abstracts in English
Kubono, Shigeru*; Teranishi, Takashi*; Notani, Masahiro*; Yamaguchi, Hidetoshi*; Saito, Akito*; He, J. J.*; Wakabayashi, Yasuo*; Fujikawa, Hisashi*; Amadio, G.*; Baba, Hidetada*; et al.
Nuclear Physics A, 758, p.733 - 736, 2005/07
Times Cited Count:1 Percentile:14.46(Physics, Nuclear)With using RNB from CRIB, proton inelastic scattering was observed. From this experiment, some resonance parameters have been deduced for the key reaction, at the explosive hydrogen burning stage in stars. Proton inelastic scattering of are also reported.
Kondo, Yasuhiro; Akikawa, Hisashi; Anami, Shozo*; Asano, Hiroyuki*; Fukui, Yuji*; Igarashi, Zenei*; Ikegami, Kiyoshi*; Ikegami, Masanori*; Ito, Takashi; Kawamura, Masato*; et al.
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.156 - 158, 2004/08
A commissioning of the J-PARC linac DTL1 is now under way at KEK. A 30mA H beam was accelerated to 19.7-MeV, and 100% transmission was obtained with a 20-msec-pulse-width and 12.5-Hz-repetition beam. In this paper, present status of the DTL1 commissioning and preliminary results of the commissioning, such as emittance measurements, are presented.