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Journal Articles

Completion of solidification and stabilization for Pu nitrate solution to reduce potential risks at Tokai Reprocessing Plant

Mukai, Yasunobu; Nakamichi, Hideo; Kobayashi, Daisuke; Nishimura, Kazuaki; Fujisaku, Sakae; Tanaka, Hideki; Isomae, Hidemi; Nakamura, Hironobu; Kurita, Tsutomu; Iida, Masayoshi*; et al.

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 8 Pages, 2017/04

TRP has stored the plutonium in solution state for long-term since the last PCDF operation in 2007 was finished. After the great east Japan earthquake in 2011, JAEA had investigated the risk against potential hazard of these solutions which might lead to make hydrogen explosion and/or boiling of the solution accidents with the release of radioactive materials to the public when blackout. To reduce the risk for storing Pu solution (about 640 kg Pu), JAEA planned to perform the process operation for the solidification and stabilization of the solution by converted into MOX powder at PCDF in 2013. In order to perform PCDF operation without adaption of new safety regulation, JAEA conducted several safety measures such as emergency safety countermeasures, necessary security and safeguards (3S) measures with understanding of NRA. As a result, the PCDF operation had stared on 28th April, 2014, and successfully completed to convert MOX powder on 3rd August, 2016 for about 2 years as planned.

Journal Articles

Insights into the proton transfer mechanism of a bilin reductase PcyA following neutron crystallography

Unno, Masayoshi*; Ishikawa, Kumiko*; Kusaka, Katsuhiro*; Tamada, Taro; Hagiwara, Yoshinori*; Sugishima, Masakazu*; Wada, Kei*; Yamada, Taro*; Tomoyori, Katsuaki; Hosoya, Takaaki*; et al.

Journal of the American Chemical Society, 137(16), p.5452 - 5460, 2015/04

 Times Cited Count:23 Percentile:65.97(Chemistry, Multidisciplinary)

Phycocyanobilin, a light-harvesting and photoreceptor pigment in higher plants, algae, and cyanobacteria, is synthesized from biliverdin IX$$alpha$$ (BV) by phycocyanobilin:ferredoxin oxidoreductase (PcyA) via two steps of two-proton-coupled two-electron reduction. We determined the neutron structure of PcyA from cyanobacteria complexed with BV, revealing the exact location of the hydrogen atoms involved in catalysis. Notably, approximately half of the BV bound to PcyA was BVH$$^{+}$$, a state in which all four pyrrole nitrogen atoms were protonated. The protonation states of BV complemented the protonation of adjacent Asp105. The "axial "water molecule that interacts with the neutral pyrrole nitrogen of the A-ring was identified. His88 N$$delta$$ was protonated to form a hydrogen bond with the lactam O atom of the BV A-ring. His88 and His74 were linked by hydrogen bonds via H$$_{3}$$O$$^{+}$$. These results imply that Asp105, His88, and the axial water molecule contribute to proton transfer during PcyA catalysis.

Journal Articles

Status of development of Lithium Target Facility in IFMIF/EVEDA project

Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Hoashi, Eiji*; Fukada, Satoshi*; Suzuki, Akihiro*; Yagi, Juro*; Tsuji, Yoshiyuki*; et al.

Proceedings of Plasma Conference 2014 (PLASMA 2014) (CD-ROM), 2 Pages, 2014/11

In the IFMIF/EVEDA (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activity), the validation tests of the EVEDA lithium test loop with the world's highest flow rate of 3000 L/min was succeeded in generating a 100 mm-wide and 25 mm-thick free-surface lithium flow steadily under the IFMIF operation condition of a high-speed of 15 m/s at 250$$^{circ}$$C in a vacuum of 10 $$^{-3}$$ Pa. Some excellent results of the recent engineering validations including lithium purification, lithium safety, and remote handling technique were obtained, and the engineering design of lithium facility was also evaluated. These results will advance greatly the development of an accelerator-based neutron source to simulate the fusion reactor materials irradiation environment as an important key technology for the development of fusion reactor materials.

Journal Articles

Improvement of seismic observation systems in JOYO

Sumino, Kozo; Suto, Masayoshi; Tanaka, Akihiro

UTNL-R-0483, p.7_1 - 7_10, 2013/03

no abstracts in English

Journal Articles

The SNARE protein SYP71 expressed in vascular tissues is involved in symbiotic nitrogen fixation in ${it Lotus japonicus}$ nodules

Hakoyama, Tsuneo*; Oi, Ryo*; Hazuma, Kazuya*; Suga, Eri*; Adachi, Yuka*; Kobayashi, Mayumi*; Akai, Rie*; Sato, Shusei*; Fukai, Eigo*; Tabata, Satoshi*; et al.

Plant Physiology, 160(2), p.897 - 905, 2012/10

 Times Cited Count:27 Percentile:72.5(Plant Sciences)

Journal Articles

Preparation and characterization of the simulated burnup americium; Containing uranium-plutonium mixed oxide fuel

Tanaka, Kosuke; Osaka, Masahiko; Miwa, Shuhei; Hirosawa, Takashi; Kurosaki, Ken*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Journal of Nuclear Materials, 420(1-3), p.207 - 212, 2012/01

 Times Cited Count:5 Percentile:42.85(Materials Science, Multidisciplinary)

In order to investigate the effect on fuel thermophysical properties when adding americium and selected fission products to uranium-plutonium mixed fuel, simulated low decontamination MOX fuel with high burn-ups to 250 GWd/t, has been prepared and subjected to characterization tests, elastic moduli measurements, melting temperature measurement.

Journal Articles

Isolation and characterization of the fragrant cyclamen ${it O}$-methyltransferase involved in flower coloration

Akita, Yusuke; Kitamura, Satoshi; Hase, Yoshihiro; Narumi, Issei; Ishizaka, Hiroshi*; Kondo, Emiko*; Kameari, Naoko*; Nakayama, Masayoshi*; Tanikawa, Natsu*; Morita, Yasumasa*; et al.

Planta, 234(6), p.1127 - 1136, 2011/12

 Times Cited Count:22 Percentile:62.41(Plant Sciences)

Journal Articles

Fluvial terrace and geomorphology in the Tokigawa (Shonaigawa) river basin since the middle Pleistocene

Tajikara, Masayoshi*; Yasue, Kenichi; Yanagida, Makoto*; Furusawa, Akira*; Tanaka, Norifumi*; Morita, Yoshimune*; Sugai, Toshihiko

Chirigaku Hyoron, 84(2), p.118 - 130, 2011/03

Many papers reported that Quaternary climate and sea-level fluctuations have controlled riverbed elevation in the river basins in the northeastern Japan. However, in the southwestern Japan, such climatic-controlled riverbed fluctuations have not been reported, except a few reports based on uncertain chronological data. In this research, we investigated fluvial terraces along the Tokigawa river that flows through the low relief mountainous areas, and examined whether riverbed fluctuations similar to these in rivers in the northeastern Japan occurred in the river basin. We mapped fluvial terraces based on air photo analysis, and inferred the age and climate at the time of formation of these terraces based on $$^{14}$$C dating, tephra analysis, and pollen analysis. Based on results of these analyses, we concluded that the fluvial terraces in the river basin have been formed in consequence of the riverbed fluctuation linked to the climate change.

Journal Articles

Red-purple flower due to delphinidin 3,5-diglucoside, a novel pigment for ${it Cyclamen}$ spp., generated by ion-beam irraidation

Kondo, Emiko*; Nakayama, Masayoshi*; Kameari, Naoko*; Tanikawa, Natsu*; Morita, Yasumasa*; Akita, Yusuke; Hase, Yoshihiro; Tanaka, Atsushi; Ishizaka, Hiroshi*

JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 65, 2011/01

no abstracts in English

Journal Articles

Effect of americium and simulated fission products addition on oxygen potential of uranium-plutonium mixed oxide fuels

Tanaka, Kosuke; Osaka, Masahiko; Kurosaki, Ken*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Materials Research Society Symposium Proceedings, Vol.1215, p.95 - 100, 2010/10

In order to investigate the effect of MAs and FP addition on the oxygen potential of MOX fuels, thermogravimetric analysis (TGA) were carried out. MOX fuels with Am and 26 kinds of fission product elements (FPs), simulating low-decontamination MOX fuel and high burn-up to 250 GWd/t, were prepared by a conventional powder metallurgical route in a glove box. The oxygen potentials for simulating low-decontamination MOX fuels were higher than the fuels without FPs and increased positively with increasing simulated burn-up.

Journal Articles

Thermal conductivities of Cs-$$M$$-O ($$M$$ = Mo or U) ternary compounds

Tokushima, Kazuyuki*; Tanaka, Kosuke; Kurosaki, Ken*; Gima, Hiromichi*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Materials Research Society Symposium Proceedings, Vol.1215, p.151 - 156, 2010/10

The thermal diffusivities of Cs$$_{2}$$MoO$$_{4}$$ and Cs$$_{2}$$UO$$_{4}$$ using samples fabricated by hot press and SPS techniques were measured by a laser flash method in the range from room temperature to 823 K for Cs$$_{2}$$MoO$$_{4}$$ and to 900 K for Cs$$_{2}$$UO$$_{4}$$. The thermal conductivities of these cesium ternary oxides were quite low compared with UO$$_{2}$$ and MOX fuel. This is consistent with previous findings. These results would be useful for evaluating the thermal performance of MOX fuels at the high burn-up region in the fast reactors.

Journal Articles

Oxygen potential of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$

Osaka, Masahiko; Tanaka, Kosuke; Miwa, Shuhei; Kurosaki, Ken*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Materials Research Society Symposium Proceedings, Vol.1215, p.199 - 203, 2010/10

Oxygen potentials of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ were experimentally determined by means of thermogravimetric analysis as a function of non-stoichiometry at 1173 and 1273 K. Oxygen potentials of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ at each temperature increased with increase of O/M ratio (= 2-x) and steep increases of the oxygen potentials toward O/M = 2 were observed. These characteristics are typical for non-stoichiometric fluorite-type actinides dioxides. The oxygen potentials of (Th$$_{0.7}$$Ce$$_{0.3}$$)O$$_{2-x}$$ were similar to those of CeOO$$_{2-x}$$ when they were plotted as a function of average Ce valence.

Journal Articles

Chemical states of fission products and actinides in irradiated oxide fuels analyzed by thermodynamic calculation and post-irradiation examination

Kurosaki, Ken*; Tanaka, Kosuke; Osaka, Masahiko; Oishi, Yuji*; Muta, Hiroaki*; Uno, Masayoshi*; Yamanaka, Shinsuke*

Proceedings of Joint International Conference of 7th Supercomputing in Nuclear Application and 3rd Monte Carlo (SNA + MC 2010) (USB Flash Drive), 4 Pages, 2010/10

It is important to understand the behavior of fission products and actinides under irradiation. In the present study, the chemical states of fission products and actinides in irradiated oxide fuels were evaluated by both thermodynamic equilibrium calculation and post-irradiation examination.

Journal Articles

Comparative analysis of floral pigmentation between wild-type and white-flowered varieties of ${it Cyclamen graecum}$

Akita, Yusuke; Ishizaka, Hiroshi*; Nakayama, Masayoshi*; Shimada, Akihiko; Kitamura, Satoshi; Hase, Yoshihiro; Narumi, Issei; Tanaka, Atsushi

Journal of Horticultural Science & Biotechnology, 85(5), p.437 - 443, 2010/09

The flower colour of ${it Cyclamen graecum}$ gra6 (wild-type) is pink-purple in the flower. On the other hand, flowers of ${it C. graecum}$ gra50 (white-flowered variant) exhibit a white colour in its flower. In this study, the relationship between floral pigmentation and expression of several anthocyanin biosynthesis genes was investigated in ${it C. graecum}$ gra6 and gra50. The pigments in the flower consist mainly of malvidin 3,5-diglucoside in gra6. White-flowered ${it C. graecum}$ gra50 possessed lower amounts of anthocyanins, but higher amounts of flavonols compared to gra6. Gene expression analysis demonstrated that expression of the dihydroflavonol 4-reductase gene 2 (${it CgraDFR2}$) was lower in gra50 compared with gra6, whereas the expression of other key genes did not differ greatly. These results suggest that the white-flowered variant of gra50 may result from a defect in expression of the ${it CgraDFR2}$ gene.

Journal Articles

${it TOO MUCH LOVE}$, a root regulator associated with the long-distance control of nodulation in ${it Lotus japonicus}$

Magori, Shimpei*; Kira, Erika*; Shibata, Satoshi*; Umehara, Yosuke*; Kochi, Hiroshi*; Hase, Yoshihiro; Tanaka, Atsushi; Sato, Shusei*; Tabata, Satoshi*; Kawaguchi, Masayoshi*

Molecular Plant-Microbe Interactions, 22(3), p.259 - 268, 2009/03

 Times Cited Count:89 Percentile:92.52(Biochemistry & Molecular Biology)

Legume plants tightly control the development and number of symbiotic root nodules. In ${it Lotus japonicus}$, this regulation required ${it HAR1}$ in the shoots, suggesting that a long-distance communication between the shoots and the roots may exist. To better understand its molecular basis, we isolated and characterized a novel hypernodulating mutant of ${it L. japonicus}$ named ${it too much love}$ (${it tml}$). Reciprocal grafting with wild type showed that ${it tml}$ hypernodulation is determined by the root genotype. Moreover, grafting a ${it har1}$ shoot onto a ${it tml}$ rootstock did not exhibit any obvious additive effects on the nodule number. These observations indicate that a shoot factor ${it HAR1}$ and a root factor ${it TML}$ participate in the same genetic pathway which governs the long-distance signaling of nodule number control. ${it TML}$ may function downstream of ${it HAR1}$ and the gene product ${it TML}$ might serve as a receptor or mediator of unknown mobile signal molecules that are transported from the shoots to the roots.

Journal Articles

Red-purple flower due to delphinidin 3,5-diglucosides, a novel pigment for ${it Cyclamen}$ spp., generated by ion-beam irradiation

Kondo, Emiko*; Nakayama, Masayoshi*; Kameari, Naoko*; Tanikawa, Natsu*; Morita, Yasumasa*; Akita, Yusuke; Hase, Yoshihiro; Tanaka, Atsushi; Ishizaka, Hiroshi*

Plant Biotechnology, 26(5), p.565 - 569, 2009/01

 Times Cited Count:27 Percentile:65.26(Biotechnology & Applied Microbiology)

Fragrant cyclamen cultivar (${it C. persicum}$ $$times$$ ${it C. purpurascens}$), that bloomed purple flower containing malvidin 3,5-diglucoside as the major anthocyanin, was irradiated with a 320-MeV carbon-ion beam at 0-16 Gy to increase flower color variation by mutation. Some of the M2 plants derived from self-pollination of M1 plants irradiated at 2 Gy were flower-color mutants that retained desirable flower shape, flower size, and leaf color. One of the mutants bloomed novel red-purple flowers, the major anthocyanin of which was delphinidin 3,5-diglucoside. Because the major anthocyanins in flowers of ${it Cyclamen}$ spp. were previously restricted to malvidin, peonidin, and cyanidin types, the generation of a cyclamen containing mostly the delphinidin-type anthocyanin is an important breakthrough in cyclamen breeding. We expect this mutant to become not only a commercial cultivar itself, but also a valuable genetic resource for cyclamen breeding.

Journal Articles

Operating experience of the J-PARC linac

Hasegawa, Kazuo; Asano, Hiroyuki; Chishiro, Etsuji; Hori, Toshihiko; Ito, Takashi; Kobayashi, Tetsuya; Kondo, Yasuhiro; Namekawa, Yuya; Oguri, Hidetomo; Okoshi, Kiyonori; et al.

Proceedings of 24th International Linear Accelerator Conference (LINAC 2008) (CD-ROM), p.55 - 57, 2009/00

The beam commissioning of the J-PARC linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac has delivered beams to the 3 GeV Rapid Cycling Synchrotron for its commissioning, and then, the subsequent Main Ring Synchrotron and the neutron target commissioning. The linac uses a Cs-free LaB$$_{6}$$-driven ion source and 20 units of 324 MHz klystrons. As of June 2008, the operation times are about 3,000 and 6,000 hours for the ion source and the RF source, respectively. The operating experience of the linac is described.

Journal Articles

Latest design of liquid lithium target in IFMIF

Nakamura, Hiroo; Agostini, P.*; Ara, Kuniaki; Cevolani, S.*; Chida, Teruo*; Ciotti, M.*; Fukada, Satoshi*; Furuya, Kazuyuki*; Garin, P.*; Gessii, A.*; et al.

Fusion Engineering and Design, 83(7-9), p.1007 - 1014, 2008/12

 Times Cited Count:14 Percentile:70.13(Nuclear Science & Technology)

This paper describes the latest design of liquid lithium target system in IFMIF. Design requirement of the Li target is to provide a stable Li jet with a speed of 20 m/s to handle an averaged heat flux of 1 GW/m$$^{2}$$. A double reducer nozzle and a concaved flow are applied to the target design. On Li purification, a cold trap and two kinds of hot trap are applied to control impurities below permissible levels. Nitrogen concentration shall be controlled below 10 wppm by one of the hot trap. Tritium concentration shall be controlled below 1 wppm by an yttrium hot trap. To maintain reliable continuous operation, various diagnostics are attached to the target assembly. Among the target assembly, a back-plate made of RAFM is located in the most severe region of neutron irradiation (50 dpa/y). Therefore, two design options of replaceable back wall and their remote handling systems are under investigation.

Journal Articles

Iodine-129 measurements in soil samples from Dolon village near the Semipalatinsk Nuclear Test Site

Endo, Satoru*; Tomita, Jumpei*; Tanaka, Kenichi*; Yamamoto, Masayoshi*; Fukutani, Satoshi*; Imanaka, Tetsuji*; Sakaguchi, Aya*; Amano, Hikaru; Kawamura, Hidehisa*; Kawamura, Hisao*; et al.

Radiation and Environmental Biophysics, 47(3), p.359 - 365, 2008/07

 Times Cited Count:5 Percentile:23.04(Biology)

Dolon village located about 60 km from the border of the Semipalatinsk Nuclear Test Site is known to be heavily contaminated by the first USSR atomic bomb test in August 1949. Soil samples around Dolon were taken in October 2005 in an attempt to evaluate internal thyroid dose arising from incorporation of radioiodine isotopes (mainly $$^{131}$$I). Iodine-129 in soil was measured by using the technique of Accelerator Mass Spectrometry. From the relationship between $$^{129}$$I and $$^{137}$$Cs (corrected for background and decay from 1949 to 2005) accumulated levels, the background level of $$^{129}$$I and the $$^{129}$$I/$$^{137}$$Cs ratio around Dolon were estimated to be (6.4 $$pm$$0.4) $$times$$ 10$$^{13}$$ atoms m$$^{-2}$$ and 0.25 $$pm$$0.16, respectively. This $$^{129}$$I/$$^{137}$$Cs ratio is almost similar to the fission yield ratio for $$^{239}$$Pu fast fission (0.24).

Journal Articles

Tobacco BY-2 cells have a transient and leaky DNA-damage checkpoint at G$$_{2}$$/M phase after $$gamma$$-ray irradiation

Yokota, Yuichiro; Funayama, Tomoo; Wada, Seiichi*; Hase, Yoshihiro; Kobayashi, Yasuhiko; Inoue, Masayoshi*; Tanaka, Atsushi; Narumi, Issei

JAEA-Review 2007-060, JAEA Takasaki Annual Report 2006, P. 69, 2008/03

no abstracts in English

104 (Records 1-20 displayed on this page)