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Journal Articles

$$^{225}$$Ac metallofullerene; Toward $$^{225}$$Ac nanogenerator in fullerene

Akiyama, Kazuhiko*; Haba, Hiromitsu*; Sueki, Keisuke*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Nagame, Yuichiro; Katada, Motomi*

Chemistry Letters, 38(10), p.978 - 979, 2009/09

 Times Cited Count:9 Percentile:39.61(Chemistry, Multidisciplinary)

We report on the successful production of a metallofullerene encapsulating the radioactive tracer $$^{225}$$Ac and on its electronic properties studied by radiochromatography. Considering the number of $$pi$$-electrons on the fullerene cage estimated from an HPLC retention time on the 5PBB column and the general oxidation state of Ac (+3), a chemical species of the dominant chromatographic peak is suggested to be Ac@C$$_{82}$$.

Journal Articles

Combined high-resolution neutron and X-ray analysis of inhibited elastase confirms the active-site oxyanion hole but rules against a low-barrier hydrogen bond

Tamada, Taro; Kinoshita, Takayoshi*; Kurihara, Kazuo; Adachi, Motoyasu; Ohara, Takashi; Imai, Keisuke*; Kuroki, Ryota; Tada, Toshiji*

Journal of the American Chemical Society, 131(31), p.11033 - 11040, 2009/07

 Times Cited Count:48 Percentile:77.51(Chemistry, Multidisciplinary)

To help resolve long-standing questions regarding the catalytic activity of the serine proteases the structure of porcine pancreatic elastase has been analyzed by high-resolution neutron and X-ray crystallography. In order to mimic the tetrahedral transition intermediate a peptidic inhibitor was used. A single large crystal was used to collect room-temperature neutron data to 1.65 ${AA}$ resolution and X-ray data to 1.20 ${AA}$ resolution. Another crystal provided a low-temperature X-ray data set to 0.94 ${AA}$ resolution. The neutron data are to higher resolution than previously reported for a serine protease and the X-ray data are comparable with other studies. The neutron and X-ray data show that the hydrogen bond between His57 and Asp102 (chymotrypsin numbering) is 2.60 ${AA}$ in length and that the hydrogen-bonding hydrogen is 0.80-0.96 ${AA}$ from the histidine nitrogen. This is not consistent with a low-barrier hydrogen which is predicted to have the hydrogen midway between the donor and acceptor atom. The observed interaction between His57 and Asp102 is essentially a short but conventional hydrogen bond, sometimes described as a short ionic hydrogen bond. The neutron analysis also shows that the oxygen of the oxopropyl group of the inhibitor is present as an oxygen anion rather than a hydroxyl group, supporting the role of the "oxyanion hole" in stabilizing the tetrahedral intermediate in catalysis.

Journal Articles

A Metallofullerene that encapsulates $$^{225}$$Ac

Akiyama, Kazuhiko*; Haba, Hiromitsu*; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Sueki, Keisuke*; Nagame, Yuichiro; Katada, Motomi*

Journal of Radioanalytical and Nuclear Chemistry, 280(2), p.329 - 331, 2009/05

 Times Cited Count:7 Percentile:48.67(Chemistry, Analytical)

The properties of a metallofullerene that encapsulates $$^{225}$$Ac were studied by radio-chromatographic methods. The results of chromatography on a Buckyclutcher column suggest that there are some metallofullerene isomers of AcC$$_{82}$$. The identical HPLC retention time of the major AcC$$_{82}$$ peak with that of La@C$$_{82}$$ indicates that the structure of one of the AcC$$_{82}$$ isomers is the same as La@C$$_{82}$$.

Journal Articles

Status on seismic design and verification for ITER in Japan

Takeda, Nobukazu; Nakahira, Masataka; Tada, Eisuke; Fujita, Satoshi*; Fujita, Takafumi*

Nihon Jishin Kogakkai Rombunshu (Internet), 4(3), p.298 - 304, 2004/04

ITER is a Tokamak-type international fusion experimental device composed of superconducting magnets, a vacuum vessel, and so on. These are operated at a quie wide temperature ranging from 4K to 200 degree C. For this, multiple plates have been chosen as the machine support so as to peovide flexibility in the radial direction while keeping high rigidity vertically. This results in a low natural frequency of around 4Hz in the horizontal direction. Since those structures are designed in accordance with the IAEA seismic acceleration of 0.2g as a reference, a seismic isolation is required if earthquake-proof larger than 0.2g is necessary. Considering these conditions, analytical and experimental studies have been conducted to characterize the ITER dynamic response in Japan. This paper outlines the latest status on seismic design for ITER in Japan and evaluation on tokamak dynamic response and verification tests using scaled tokamak model.

Journal Articles

Analysis of benchmark results for reactor physics of LWR next generation fuels

Kitada, Takanori*; Okumura, Keisuke; Unesaki, Hironobu*; Saji, Etsuro*

Proceedings of International Conference on Physics of Fuel Cycles and Advanced Nuclear Systems; Global Developments (PHYSOR 2004) (CD-ROM), 8 Pages, 2004/04

Burnup calculation benchmark has been carried out for the LWR next generation fuels aiming at high burnup up to 70 GWd/t with UO$$_{2}$$ and MOX. Based on the submitted results by many benchmark participants, the present status of calculation accuracy has been confirmed for reactor physics parameters of the LWR next generation fuels, and the factors causing the calculation differences were analyzed in detail. Moreover, the future experiments and research subjects necessary to reduce the calculation differences were discussed and proposed.

JAEA Reports

Revised version of tokamak transient simulation code SAFALY, 2

Senda, Ikuo*; Fujieda, Hirobumi; Neyatani, Yuzuru; Tada, Eisuke; Shoji, Teruaki

JAERI-Data/Code 2003-012, 73 Pages, 2003/07

JAERI-Data-Code-2003-012.pdf:3.45MB

The tokamak transient simulation code, named SAFALY, was revised recently and the sensitivity analyses on the parameters in the code were carried out. This report is composed of two volumes. The formulation and the parameters in modeling the plasma and in-vessel components are described in the first volume. In this second volume, the results of the sensitivity studies are reported. The sensitivity studies were performed in two steps. In the first step, the responses of plasmas in the occurrence of plasma disturbances were analyzed for various initial conditions. For each disturbance, the initial condition of the plasma, which gave the largest increase of the fusion power, was identified. In the second step, by using initial conditions derived in the first step, the sensitivities of plasma reactions with respect to variation of the parameters in SAFALY code were analyzed. In the analyses, the increase of the fueling, the increase of the plasma confinement improvement factor and the increase of the auxiliary heating power were considered as plasma disturbances.

JAEA Reports

Revised version of tokamak transient simulation code SAFALY, 1

Senda, Ikuo*; Fujieda, Hirobumi; Neyatani, Yuzuru; Tada, Eisuke; Shoji, Teruaki

JAERI-Data/Code 2003-008, 37 Pages, 2003/06

JAERI-Data-Code-2003-008.pdf:1.58MB

Tokamak transient simulation code, named SAFALY, was revised. SAFALY code has been developed to simulate transient events in Tokamaks. Modeling of the plasma and algorithms of the simulation were revised. The code was also modified to deal with the variation of the plasma current. The code was improved to allow flexible modeling of in-vessel components. The data transfer between SAFALY and related codes was arranged to prepare data required in analyses with SAFALY, such as the distributions of heat/neutron loads and the radiation form factor between in-vessel components. The report is composed of two volumes. The formulation and the parameters in modeling plasma and in-vessel components are described in this first volume. Examples of simulation results, using the design of ITER-FDR in 2001, are presented and general properties of plasmas' responses with respect to perturbations are discussed. The results of the sensitivity studies with respect to simulation parameters and initial conditions will be reported in the second volume.

Journal Articles

Update status of benchmark activity for reactor physics study of LWR next generation fuels

Unesaki, Hironobu*; Okumura, Keisuke; Kitada, Takanori*; Saji, Etsuro*

Transactions of the American Nuclear Society, 88, p.436 - 438, 2003/06

In order to investigate the calculation accuracy of the nuclear characteristics of LWR next generation fuels, the Research Committee on Reactor Physics organized by JAERI has proposed "Reactor Physics Benchmark for LWR Next Generation Fuels". The next generation fuels aim at very high burn-up of about 70GWd/t in PWR or BWR with UO$$_{2}$$ or MOX fuels whose fissile enrichments may exceed the Japanese regulatory limitations for the current LWR fuels such as 5wt.% U-235. Until now, twelve organizations have pariticipated in the benchmark activity. From the comparison with the cell burn-up calculation results using different codes and library data, status of the calculation accuracy and future subjects are clarified.

Journal Articles

Approach for safety assurance and structural integrity of ITER

Tada, Eisuke; Hada, Kazuhiko; Maruo, Takeshi; Safety Design/Evaluation Group

Purazuma, Kaku Yugo Gakkai-Shi, 78(11), p.1145 - 1156, 2002/11

no abstracts in English

Journal Articles

Benchmark results of burn-up calculation for LWR next generation fuels

Okumura, Keisuke; Unesaki, Hironobu*; Kitada, Takanori*; Saji, Etsuro*

Proceedings of International Conference on the New Frontiers of Nuclear Technology; Reactor Physics, Safety and High-Performance Computing (PHYSOR 2002) (CD-ROM), 10 Pages, 2002/10

In order to investigate the calculation accuracy of the nuclear characteristics of LWR next generation fuels, the Research Committee on Reactor Physics organized by Japan Atomic Energy Research Institute has proposed "Reactor Physics Benchmark for LWR Next Generation Fuels". The next generation fuels aim at very high burn-up of about 70GWd/t in PWR or BWR with UO2 or MOX fuels whose fissile enrichments may exceed the Japanese regulatory limitations for the current LWR fuels such as 5wt.% U-235. Twelve organizations have carried out the analyses of the benchmark problems with different codes and data, and their submitted results have been compared. As a result, status of accuracy with the current data and method and some problems to be solved in the future were clarified.

Journal Articles

Study of metallofullerenes encapsulating actinides

Akiyama, Kazuhiko; Sueki, Keisuke*; Tsukada, Kazuaki; Yaita, Tsuyoshi; Miyake, Yoko*; Haba, Hiromitsu*; Asai, Masato; Kodama, Takeshi*; Kikuchi, Koichi*; Otsuki, Tsutomu*; et al.

Journal of Nuclear and Radiochemical Sciences, 3(1), p.151 - 154, 2002/06

The oxidation state of actinide elements encapsulated in fullerenes is studied. HPLC elution behavior of actinide-fullerenes is classified into two groups; the elution behavior of the first group, encapsulating U, Np, and Am, is similar to that of the light lanthanide-fullerenes, such as La, Ce, Pr, and Nd, while the behavior of the second group, encapsulating Th and Pa, is quite different from that of any lanthanide-fullerenes. The chemical species in the main HPLC elution peak of each group were identified as M@C82 and M@C84 (M = metal atom) from the mass of the U and Th fullerenes, respectively. The oxidation states of the U and Th atoms in the fullerenes were deduced to be 3+ and 4+, respectively, from the UV/vis/NIR absorption and XANES spectroscopy.

Journal Articles

Safety design concepts for ITER-tritium facility; Toward construction in Japan

Ohira, Shigeru; Tada, Eisuke; Hada, Kazuhiko; Neyatani, Yuzuru; Maruo, Takeshi; Hashimoto, Masayoshi*; Araki, Takao*; Nomoto, Kazuhiro*; Tsuru, Daigo; Ishida, Toshikatsu*; et al.

Fusion Science and Technology, 41(3), p.642 - 646, 2002/05

no abstracts in English

Journal Articles

Main features of ITER vacuum vessel and approach to code application

Nakahira, Masataka; Takeda, Nobukazu; Hada, Kazuhiko; Tada, Eisuke; Miya, Kenzo*; Asada, Yasuhide*

Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 7 Pages, 2002/04

The special features of Vacuum Vessel (VV) of International Thermonuclear Experimental Reactor (ITER) are complicated structure and electromagnetic load. The VV is torus shaped, double-walled structure with ribs. The electromagnetic force is not uniform. Thus the rules for axisymmetric structures and loading are not effective for ITER VV. The double ミwalled structure requires one-sided welding joints with no possibility of access from the other side. Every joints between outer wall and rib and field joints are this type. The joint between outer wall and rib is special T-joint with partial penetration. To cover these special issues on ITER VV, a new code is under development. Supporting R&Ds are planned to be material tests to obtain joint efficiency and fatigue reduction factor, UT sensitivity tests, sensitivity tests on crevice corrosion and examination-free welding for application to field joints. This paper describes the special features of ITER VV from code stand point, concept of new code and R&Ds to apply the new code to ITER VV.

JAEA Reports

Development of fabrication technology for ITER vacuum vessel

Nakahira, Masataka; Shibanuma, Kiyoshi; Kajiura, Soji*; Shibui, Masanao*; Koizumi, Koichi; Takeda, Nobukazu; Kakudate, Satoshi; Taguchi, Ko*; Oka, Kiyoshi; Obara, Kenjiro; et al.

JAERI-Tech 2002-029, 27 Pages, 2002/03

JAERI-Tech-2002-029.pdf:2.04MB

The ITER vacuum vessel (VV) R&D has progressed with the international collaborative efforts by the Japan, Russia and US Parties during the Engineering Design Activities (EDA). Fabrication and testing of a full-scale VV sector model and a port extension have yielded critical information on the fabrication and assembly technologies of the vacuum vessel, magnitude of welding distortions, dimensional accuracy and achievable tolerances during sector fabrication and field assembly. In particular, the dimensional tolerances of $$pm$$3 mm for VV sector fabrication and $$pm$$10 mm for VV sector field assembly have been achieved and satisfied the requirements of $$pm$$5 mm and $$pm$$20 mm, respectively. Also, the basic feasibility of the remote welding robot has been demonstrated. This report presents detailed fabrication and assembly technologies such as welding technology applicable to the thick wall without large distortion, field joint welding technology between sectors and remote welding technology through the VV R&D project.

Journal Articles

New cryogenic steels and design approach for ITER superconducting magnet system

Nakajima, Hideo; Hamada, Kazuya; Okuno, Kiyoshi; Hada, Kazuhiko; Tada, Eisuke

Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 8 Pages, 2002/00

The Japan Atomic Energy Research Institute (JAERI) has conducted to develop a new design code for construction and operation/maintenance of the International Thermonuclear Experimental Reactor (ITER), which will be formed as a code case of ASME B&PV Code Section III, division 4, in collaboration with the ASME international. The new design code will also include the several new techniques and materials developed for each components of ITER. This paper describes the new cryogenic steels used in the magnet system and the design approach with taking account of unique features of the ITER superconducting magnets.

JAEA Reports

Conceptual design of solid breeder blanket system cooled by supercritical water

Enoeda, Mikio; Ohara, Yoshihiro; Akiba, Masato; Sato, Satoshi; Hatano, Toshihisa; Kosaku, Yasuo; Kuroda, Toshimasa*; Kikuchi, Shigeto*; Yanagi, Yoshihiko*; Konishi, Satoshi; et al.

JAERI-Tech 2001-078, 120 Pages, 2001/12

JAERI-Tech-2001-078.pdf:8.3MB

This report is a summary of the design works, which was discussed in the design workshop held in 2000 for the demonstration (DEMO) blanket aimed to strengthen the commercial competitiveness and technical feasibility simultaneously. The DEMO blanket must supply the feasibility and experience of the total design of the power plant and the materials. This conceptual design study was performed to determine the updated strategy and goal of the R&D of the DEMO blanket which applies the supercritical water cooling proposed in A-SSTR, taking into account the recent progress of the plasma research and reactor engineering technology.

Journal Articles

Study on decay heat removal of compact ITER

Tsuru, Daigo; Neyatani, Yuzuru; Araki, Takao*; Nomoto, Kazuhiro*; Ohira, Shigeru; Maruo, Takeshi; Hashimoto, Masayoshi*; Hada, Kazuhiko; Tada, Eisuke

Fusion Engineering and Design, 58-59, p.985 - 989, 2001/11

 Times Cited Count:3 Percentile:28.03(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Fusion reactor technology; Challenge to future energy

Seki, Masahiro; Hishinuma, Akimichi; Kurihara, Kenichi; Akiba, Masato; Abe, Tetsuya; Ishitsuka, Etsuo; Imai, Tsuyoshi; Enoeda, Mikio; Ohira, Shigeru; Okumura, Yoshikazu; et al.

Kaku Yugoro Kogaku Gairon; Mirai Enerugi Eno Chosen, 246 Pages, 2001/09

no abstracts in English

Journal Articles

Development of a control system for a heavy object handling manipulator; Application to a remote maintenance system for ITER blanket module

Yoshimi, Takashi*; Kakudate, Satoshi; Tada, Eisuke; Tsuji, Koichi*; Miyagawa, Shinichi*; Kubo, Tomomi*

Nihon Robotto Gakkai-Shi, 19(6), p.766 - 774, 2001/09

no abstracts in English

Journal Articles

Safety activities in JAERI related to ITER

Ohira, Shigeru; Tada, Eisuke; Hada, Kazuhiko; Neyatani, Yuzuru; Maruo, Takeshi; Hashimoto, Masayoshi*; Araki, Takao*; Nomoto, Kazuhiro*; Tsuru, Daigo; Ishida, Toshikatsu*; et al.

Fusion Engineering and Design, 54(3-4), p.515 - 522, 2001/04

 Times Cited Count:3 Percentile:28.03(Nuclear Science & Technology)

no abstracts in English

130 (Records 1-20 displayed on this page)