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Journal Articles

Field test around Fukushima Daiichi Nuclear Power Plant site using improved Ce:Gd$$_{3}$$(Al,Ga)$$_{5}$$O$$_{12}$$ scintillator Compton camera mounted on an unmanned helicopter

Shikaze, Yoshiaki; Nishizawa, Yukiyasu; Sanada, Yukihisa; Torii, Tatsuo; Jiang, J.*; Shimazoe, Kenji*; Takahashi, Hiroyuki*; Yoshino, Masao*; Ito, Shigeki*; Endo, Takanori*; et al.

Journal of Nuclear Science and Technology, 53(12), p.1907 - 1918, 2016/12

 Times Cited Count:24 Percentile:96.18(Nuclear Science & Technology)

The Compton camera was improved for use with the unmanned helicopter. Increase of the scintillator array from 4$$times$$4 to 8$$times$$8 and expanse of the distance between the two layers contributed to the improvements of detection efficiency and angular resolution, respectively. Measurements were performed over the riverbed of the Ukedo river of Namie town in Fukushima Prefecture. By programming of flight path and speed, the areas of 65 m $$times$$ 60 m and 65 m $$times$$ 180 m were measured during about 20 and 30 minutes, respectively. By the analysis the air dose rate maps at 1 m height were obtained precisely with the angular resolution corresponding to the position resolution of about 10 m from 10 m height. Hovering flights were executed over the hot spot areas for 10-20 minutes at 5-20 m height. By using the reconstruction software the $$gamma$$-ray images including the hot spots were obtained with the angular resolution same as that evaluated in the laboratory (about 10$$^{circ}$$).

Journal Articles

Preparation and evaluation of an astatine-211-labeled sigma receptor ligand for $$alpha$$ radionuclide therapy

Ogawa, Kazuma*; Mizuno, Yoshiaki*; Washiyama, Koshin*; Shiba, Kazuhiro*; Takahashi, Naruto*; Kozaka, Takashi*; Watanabe, Shigeki; Shinohara, Atsushi*; Odani, Akira*

Nuclear Medicine and Biology, 42(11), p.875 - 879, 2015/11

 Times Cited Count:18 Percentile:69.85(Radiology, Nuclear Medicine & Medical Imaging)

Journal Articles

Neutron irradiation effect of high-density MoO$$_{3}$$ pellets for Mo-99 production, 2

Nishikata, Kaori; Ishida, Takuya; Yonekawa, Minoru; Kato, Yoshiaki; Kurosawa, Makoto; Kimura, Akihiro; Matsui, Yoshinori; Tsuchiya, Kunihiko; Sano, Tadafumi*; Fujihara, Yasuyuki*; et al.

KURRI Progress Report 2014, P. 109, 2015/07

As one of effective applications of the Japan Materials Testing Reactor (JMTR), JAEA has a plan to produce $$^{99}$$Mo by (n,$$gamma$$) method ((n,$$gamma$$)$$^{99}$$Mo production), a parent nuclide of $$^{99m}$$Tc. In this study, preliminary irradiation test was carried out with the high-density molybdenum trioxide (MoO$$_{3}$$) pellets in the hydraulic conveyer (HYD) of the Kyoto University Research Reactor (KUR) and the $$^{99m}$$Tc solution extracted from $$^{99}$$Mo was evaluated. After the irradiation test of the high-density MoO$$_{3}$$ pellets in the KUR, $$^{99m}$$Tc was extracted from the Mo solution and the recovery rate of $$^{99m}$$Tc achieved the target values. The $$^{99m}$$Tc solution also got the value that satisfied the standard value for $$^{99m}$$Tc radiopharmaceutical products by the solvent extraction method.

Journal Articles

The Possible interplanetary transfer of microbes; Assessing the viability of ${it Deinococcus}$ spp. under the ISS environmental conditions for performing exposure experiments of microbes in the Tanpopo mission

Kawaguchi, Yuko*; Yang, Y.*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Takasu, Masako*; Narumi, Issey*; Sato, Katsuya; Hashimoto, Hirofumi*; Nakagawa, Kazumichi*; Tanigawa, Yoshiaki*; et al.

Origins of Life and Evolution of Biospheres, 43(4-5), p.411 - 428, 2013/10

 Times Cited Count:29 Percentile:78.06(Biology)

JAEA Reports

Investigation of radionuclide distribution using aircraft for surrounding environmental survey from Fukushima Dai-ichi Nuclear Power Plant

Torii, Tatsuo; Sanada, Yukihisa; Sugita, Takeshi; Kondo, Atsuya*; Shikaze, Yoshiaki; Takahashi, Masaki; Ishida, Mutsushi; Nishizawa, Yukiyasu; Urabe, Yoshimi

JAEA-Technology 2012-036, 182 Pages, 2012/12

JAEA-Technology-2012-036.pdf:41.89MB

We carried out aerial radiation monitoring (ARM) of all Japan area in order to investigate the influence of the radio cesium which was emitted into the atmosphere by disaster of the Fukushima Dai-ichi Nuclear Power Plant of Tokyo Electric Power Co., Inc.. AMS can measure a $$gamma$$ ray quickly by flight from 300 m height above the ground. Moreover, ARM has an advantage which can grasp self-possessed quantity distribution of an air dose rate and radioactive cesium in "field", and is visually intelligible. Although there were apparatus and the technique of ARM in our country, sufficient preparations for wide area monitoring were not made. Therefore, it fixed based on the method of the U.S. Department of Energy (DOE) about the method of the conversion to all radiation dose, and the conversion method to radiocesium deposition and the method of mapping. It is possible to discriminate from a background (cosmic-ray, self-contamination and natural nuclides) at the time of western-part-of-Japan measurement by improving of the method in parallel to data acquisition. By this monitoring, it was able to check about the distribution situation of the air dose rate of the Japanese whole region, or the radioactive cesium deposition. Here, the measurement technique and a result are described.

Journal Articles

To participate in the disaster reconstruction committee formulated vision Tomioka-machi

Abe, Sadayoshi; Kuwae, Yoshiaki*; Sasaki, Satoru*; Takahashi, Kazutoshi*

Genshiryoku, hoshasen Bukaiho (Internet), (10), p.6 - 8, 2012/03

Between January 30, 2012 August 26, 2011, the support for the correct understanding of nuclear and radiation due to comments and advice to participate in disaster reconstruction committee formulated vision of the Tomioka town, as a professional Engineers, Japan was carried out, As a result, the vision I hope to go back to town Tomioka are taken together to form all townspeople have been developed.

Journal Articles

Crystal growth procedure of HIV-1 protease-inhibitor KNI-272 complex for neutron structural analysis at 1.9 ${AA}$ resolution

Shimizu, Noriko*; Sugiyama, Shigeru*; Maruyama, Mihoko*; Takahashi, Yoshinori*; Adachi, Motoyasu; Tamada, Taro; Hidaka, Koshi*; Hayashi, Yoshio*; Kimura, Toru*; Kiso, Yoshiaki*; et al.

Crystal Growth & Design, 10(7), p.2990 - 2994, 2010/06

 Times Cited Count:11 Percentile:73.7(Chemistry, Multidisciplinary)

We report crystal growth of human immunodeficiency virus 1 protease (HIV PR) in a complex with its inhibitor KNI-272 by six different methods. Comparative analysis indicates that top-seeded solution growth (TSSG) and TSSG combined with the floating and stirring technique (TSSG-FAST) are efficient strategies for rapidly obtaining large single crystals and effectively preventing polycrystallization of the seed crystal. Neutron diffraction analysis confirmed that the crystalobtained by TSSG is a high-quality single crystal. Furthermore, crystal shape was observed to be influenced by solution flow, suggesting that the degree of supersaturation significantly affects the crystal growth direction of HIV PR complex. This finding implies that the shape of the HIV PR complex crystal might be controlled by the solution flow rate.

JAEA Reports

Discussion on sealing performance required in disposal system; Preliminary study on hydraulic analysis of disposal panel

Sugita, Yutaka*; Takahashi, Yoshiaki*; Uragami, Manabu*; Kitayama, Kazumi*; Fujita, Tomo; Yui, Mikazu

JAEA-Research 2007-023, 70 Pages, 2007/03

JAEA-Research-2007-023.pdf:26.16MB

The sealing performance of a repository is very important for the safety assessment of the geological disposal system for high-level radioactive waste. NUMO and JAEA set up a technical commission to investigate sealing technology in a repository in 2004 following a cooperation agreement between these two organisations. The objectives of this commission were to present a concept of sealing performance required in the disposal system and to direct future R&D for design requirements of closure components (backfilling material, clay plug, etc.). Hydraulic analyses on tunnel intersections were carried out during the first year in 2004. This was expanded into a hydraulic analysis of a complete disposal panel with all tunnels during the second year in 2005. Since the model structure in 2005 was more complicated than the one used in 2004, the concept of equivalent permeability was adopted in and around each tunnel in the hydraulic analyses. Parameters used in the hydraulic analyses were installation positions of clay plugs, permeability of the backfilling material, permeability of disposal tunnel and directions of hydraulic gradient to estimate influences to the analytical results preliminary. Analytical results showed that flow rate in a disposal tunnel was influenced by directions of hydraulic gradient, installation of the clay plug at the both ends of each disposal tunnel and permeability of the main tunnel.

Journal Articles

The Japanese approach to developing clay-based repository concepts; An Example of design studies for the assessment of sealing strategies

Sugita, Yutaka; Fujita, Tomo; Takahashi, Yoshiaki*; Kawakami, Susumu; Umeki, Hiroyuki; Yui, Mikazu; Uragami, Manabu*; Kitayama, Kazumi*

Physics and Chemistry of the Earth, 32(1-7), p.32 - 41, 2007/00

 Times Cited Count:6 Percentile:22.71(Geosciences, Multidisciplinary)

The H12 repository concept for vitrified high-level radioactive waste was developed based on a multi-barrier system with the emphasis on robust engineered barrier performance to ensure its feasibility for a wide range of geological conditions typically observed in Japan. The buffer is clay-based and plays a very important role in the engineered barrier system (EBS). The decision to use a volunteer siting process requires maximum flexibility of the repository concept to allow it to be adapted to potential sites and hence a wide range of variants of the basic H12 repository design has been developed. In order to evaluate the feasibility and the applicability of different repository options to specific siting environments, NUMO has established a set of "design factors" which classify the aspects that need to be considered when evaluating the pros and cons of different repository options. A Na-type bentonite from Japan is used as the reference material for all clay-based repository components (buffer, backfill, clay plug, etc.). The characteristics of this bentonite (thermal, mechanical, chemical, hydraulic) have been examined with consideration of various practical constraints (limitation on the repository footprint, the influence of saline water, the interaction of hyperalkaline leachates and practical working environment, etc.). Clay-based seals, which close off the tunnels after emplacement of the EBS, may also be key components for assessment of the repository. Full analyses considering all engineered barrier components (buffer, backfill, clay plug, concrete lining, tunnel, concrete plug, host rock) that may be used in a repository will be an essential future task. As a first step towards this goal, a numerical analysis focusing on hydraulic behaviour at the intersections of the disposal tunnels and the main tunnel is presented to illustrate how the design requirements of clay-based seals can be determined.

Journal Articles

Hydraulic calculation of clay-based backfill and plug for the intersections of tunnels in the geological repository for HLW

Fujita, Tomo; Sugita, Yutaka*; Takahashi, Yoshiaki*

Australian Geomechanics, 41(4), p.89 - 95, 2006/12

In this study, three-dimensional simulations of groundwater flow are conducted to investigate the sealing performance of clay-based backfill and plug at the tunnel intersection for given hydraulic conditions around the tunnels. In the analytical results, it is found that the direction of hydraulic gradient, hydraulic conductivities of concrete and backfilling materials and the position of clay plug had impact on flow condition around the EBS.

Journal Articles

Rheo-SANS study on gelation of poly(vinyl alcohol)

Takahashi, Nobuaki; Kanaya, Toshiji*; Nishida, Koji*; Takahashi, Yoshiaki*; Arai, Masatoshi

Physica B; Condensed Matter, 385-386(1), p.810 - 813, 2006/11

 Times Cited Count:4 Percentile:23.8(Physics, Condensed Matter)

We have studied shear flow effects on physical gelation processes of poly(vinyl alcohol) solutions in a mixture of deuterated dimethyl sulfoxide and heavy water using time-resolved 2D-SANS technique with a rheological setup. Steady shear flow was applied on the sample solution after quenching from 100 $$^{circ}$$C to 25 $$^{circ}$$C, and the isothermal measurements were performed. The observed two-dimensional scattering patterns under the shear flow were isotropic while the growth rate of the scattering intensity was affected. It has been revealed in a previous report that the gelation of the solution was caused through crystallization between polymer chains to form the network. Hence, focusing on the scattering intensity from the crystallites, we have evaluated the crystallization rate. It was found that the crystallization rate was accelerated in a low shear rate region (shear rate is smaller than 5 sec$$^{-1}$$) and decreased with increasing the shear rate in a high rate region (bigger than 5 sec$$^{-1}$$) after a maximum at 5 sec$$^{-1}$$. The results suggest that the local orientation of flexible polymer chains due to the shear flow assist crystal nucleation in the low shear rate region while the once-formed crystallites are destroyed by the shear in the high shear rate region.

JAEA Reports

Discussion on sealing performance required to disposal system; Hydraulic analysis considering intersections of tunnels

Sugita, Yutaka*; Fujita, Tomo; Takahashi, Yoshiaki*; Kawakami, Susumu; Umeki, Hiroyuki; Yui, Mikazu; Uragami, Manabu*

JNC TN8400 2005-016, 49 Pages, 2005/09

JNC-TN8400-2005-016.pdf:5.45MB

The sealing performance of a repository should be considered in the safety assessment of the geological disposal system of the high level radioactive waste. Nuclear Waste Management Organization of Japan and Japan Nuclear Cycle Development Institute are examining the sealing performance of the closure components (backfilling material and clay plug) to present the concept on the sealing performance required to the disposal system, and to develop the direction for the future R&D programme for the design requirements of the closure components of the presented concepts.The first step of this examination reviewed the current status of the domestic and the international sealing technologies, summarized the repository components and the repository environments, and performed the hydraulic analysis considering components on the intersections of a main tunnel and a disposal tunnel in a disposal panel and in and around the engineered barrier system (EBS). Since all tunnels connect in the underground facility, understanding of hydraulic behaviour at the intersections of the tunnels is the important issue to estimate migration of radionuclides from the EBS, and to evaluate the required sealing performance for the disposal system. The considering components in the analysis model are the intersections of the disposal tunnel and the main tunnel, the waste package, the EBS, the backfilling material, the clay plug, the concrete plug, the excavated disturbed zone, the tunnel lining and the host rock. Alteration of the concrete material (tunnel lining and concrete plug) is described as variation of the hydraulic conductivity of it. Sites of emplacement of the clay plug are the disposal tunnel and the main tunnel. No clay plug condition is also analysed. Effect of the clay plug is discussed by the results of these analyses.

JAEA Reports

Study on Methodology for Biosphere Assessment Data

Kato, Tomoko; Suzuki, Yuji*; Makino, Hitoshi; Uchida, Masahiro; Naito, Morimasa; Wakasugi, Keiichiro*; Takahashi, Yoshiaki*

JNC TN1400 2005-024, 14 Pages, 2005/08

JNC-TN1400-2005-024.pdf:0.67MB

Biosphere assessment is positioned as part of an important factor in safety assessment to convert nuclide release rates into surface environment to measures of effect for human, such as radiation dose. In general, a lot of data are handled in the biosphere assessment, and they are based on the feature of specific site. Therefore, it is reasonable to screen parameters in order to manage the limited resource and develop the biosphere assessment effectively. JNC and NUMO established

Journal Articles

Effects of He/Electron irradiation on microstructure evolution in Be$$_{12}$$Ti

Shibayama, Tamaki*; Nakamichi, Masaru*; Uchida, Munenori*; Kawamura, Hiroshi; Kinoshita, Hiroshi*; Kiyanagi, Yoshiaki*; Takahashi, Heishichiro*; Nomura, Naoyuki*

JAERI-Conf 2004-006, p.216 - 219, 2004/03

no abstracts in English

Journal Articles

Current status of the AGS spallation target experiment

Nakashima, Hiroshi; Takada, Hiroshi; Kasugai, Yoshimi; Meigo, Shinichiro; Maekawa, Fujio; Kai, Tetsuya; Konno, Chikara; Ikeda, Yujiro; Oyama, Yukio; Watanabe, Noboru; et al.

Proceedings of 6th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-6), (OECD/NEA No.3828), p.27 - 36, 2004/00

no abstracts in English

Journal Articles

Development of a pumping laser system for X-ray laser research

Kawachi, Tetsuya; Kado, Masataka; Tanaka, Momoko; Hasegawa, Noboru; Nagashima, Keisuke; Sukegawa, Kota*; Lu, P.; Takahashi, Kenjiro; Namba, Shinichi; Koike, Masato; et al.

Applied Optics, 42(12), p.2198 - 2205, 2003/04

 Times Cited Count:27 Percentile:73.65(Optics)

no abstracts in English

Journal Articles

Neutron irradiation effect on the mechanical properties of type 316L SS welded joint

Saito, Shigeru; Fukaya, Kiyoshi*; Ishiyama, Shintaro; Amezawa, Hiroo; Yonekawa, Minoru; Takada, Fumiki; Kato, Yoshiaki; Takeda, Takashi; Takahashi, Hiroyuki*; Nakahira, Masataka

Journal of Nuclear Materials, 307-311(Part2), p.1573 - 1577, 2002/12

 Times Cited Count:1 Percentile:10.45(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Gain saturation of nickel-like silver and tin X-ray lasers by use of a tabletop pumping laser system

Kawachi, Tetsuya; Kado, Masataka; Tanaka, Momoko; Sasaki, Akira; Hasegawa, Noboru; Kilpio, A.*; Namba, Shinichi; Nagashima, Keisuke; Lu, P.; Takahashi, Kenjiro; et al.

Physical Review A, 66(3), p.033815_1 - 033815_7, 2002/09

 Times Cited Count:84 Percentile:93.54(Optics)

A silver and tin slab targets were irradiated by a line-focused CPA glass laser light. In this experiment, the laser pulses consisted of two pulses with 4 ps duration, separated by 1.2 ns. Strong amplification in the nickel-like silver and tin x-ray lasers at the wavelengths of 13.9nm and 12.0nm was demonstrated with a pumping energy of 12 J and 14 J, respectively, and gain-saturation behaviors could be seen. A hydro-dynamics simulation coupled with a collisional-radiative model was performed under the present experimental condition, and the calculated result was compared with the experimental results.

Journal Articles

Research activities on neutronics under ASTE collaboration at AGS/BNL

Nakashima, Hiroshi; Takada, Hiroshi; Kasugai, Yoshimi; Meigo, Shinichiro; Maekawa, Fujio; Kai, Tetsuya; Konno, Chikara; Ikeda, Yujiro; Oyama, Yukio; Watanabe, Noboru; et al.

Journal of Nuclear Science and Technology, 39(Suppl.2), p.1155 - 1160, 2002/08

no abstracts in English

JAEA Reports

Mechanical properties of type 316L stainless steel welded joint for vacuum vessel of ITER, 2; Neutron irradiation tests and post-irradiation experiments

Saito, Shigeru; Fukaya, Kiyoshi; Ishiyama, Shintaro; Amezawa, Hiroo; Yonekawa, Minoru; Takada, Fumiki; Kato, Yoshiaki; Takeda, Takashi; Takahashi, Hiroyuki*; Koizumi, Koichi

JAERI-Tech 2001-035, 81 Pages, 2001/06

JAERI-Tech-2001-035.pdf:18.91MB

no abstracts in English

42 (Records 1-20 displayed on this page)