Refine your search:     
Report No.
 - 
Search Results: Records 1-20 displayed on this page of 33

Presentation/Publication Type

Initialising ...

Refine

Journal/Book Title

Initialising ...

Meeting title

Initialising ...

First Author

Initialising ...

Keyword

Initialising ...

Language

Initialising ...

Publication Year

Initialising ...

Held year of conference

Initialising ...

Save select records

Journal Articles

Radioactivity and radionuclides in deciduous teeth formed before the Fukushima-Daiichi Nuclear Power Plant accident

Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.

Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05

 Times Cited Count:1 Percentile:65.97(Multidisciplinary Sciences)

Journal Articles

Development of evaluation procedure for critical current of periodically bent Nb$$_{3}$$Sn strand

Kajitani, Hideki; Ishiyama, Atsushi*; Agatsuma, Ko*; Murakami, Haruyuki; Hemmi, Tsutomu; Koizumi, Norikiyo

Teion Kogaku, 50(12), p.608 - 615, 2015/12

A cable-in-conduit (CIC) conductor using Nb$$_{3}$$Sn strand is applied to an ITER TF coil. The Nb$$_{3}$$Sn strand in the conductor is periodically bent due to electromagnetic force, which causes degradation of performance. This degradation should be evaluated to predict conductor critical current performance. In a past study, a numerical simulation model was developed to evaluate the superconductivity of a periodically bent single strand. However, this model is not suitable for application to strands in the conductor because of the extensive calculation time. The author thus developed a new analytical model with a much shorter calculation time to evaluate the performance of periodically bent strand. This new model uses the classical model concept of a high transverse resistance model (HTRM). The calculated results show good agreement with the test results of a periodically bent Nb$$_{3}$$Sn strand. This indicates that a more practical solution can be achieved when evaluating the performance of periodically bent strands. Thus, the model developed in this study can be applied to evaluate the performance of conductors incorporating many strands.

Journal Articles

Behavior of Nb$$_{3}$$Sn cable assembled with conduit for ITER central solenoid

Nabara, Yoshihiro; Suwa, Tomone; Takahashi, Yoshikazu; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Sakurai, Takeru; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; et al.

IEEE Transactions on Applied Superconductivity, 25(3), p.4200305_1 - 4200305_5, 2015/06

 Times Cited Count:0 Percentile:0(Engineering, Electrical & Electronic)

Journal Articles

Optimization of heat treatment of Japanese Nb$$_3$$Sn conductors for toroidal field coils in ITER

Nabara, Yoshihiro; Hemmi, Tsutomu; Kajitani, Hideki; Ozeki, Hidemasa; Suwa, Tomone; Iguchi, Masahide; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Koizumi, Norikiyo; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.6000605_1 - 6000605_5, 2014/06

no abstracts in English

Journal Articles

Cabling technology of Nb$$_3$$Sn conductor for ITER central solenoid

Takahashi, Yoshikazu; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Uno, Yasuhiro; et al.

IEEE Transactions on Applied Superconductivity, 24(3), p.4802404_1 - 4802404_4, 2014/06

 Times Cited Count:20 Percentile:73.53(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA) is procuring all amounts of Nb$$_3$$Sn conductors for Central Solenoid (CS) in the ITER project. Before start of mass-productions, the conductor should be tested to confirm superconducting performance in the SULTAN facility, Switzerland. The original design of cabling twist pitches is 45-85-145-250-450 mm, called normal twist pitch (NTP). The test results of the conductors with NTP was that current shearing temperature (Tcs) is decreasing due to electro-magnetic (EM) load cycles. On the other hand, the results of the conductors with short twist pitches (STP) of 25-45-80-150-450 mm show that the Tcs is stabilized during EM load cyclic tests. Because the conductors with STP have smaller void fraction, higher compaction ratio during cabling is required and possibility of damage on strands increases. The technology for the cables with STP was developed in Japanese cabling suppliers. The several key technologies will be described in this paper.

Journal Articles

Cable twist pitch variation in Nb$$_{3}$$Sn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Nabara, Yoshihiro; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Hamada, Kazuya; Matsui, Kunihiro; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 23(3), p.4801504_1 - 4801504_4, 2013/06

 Times Cited Count:11 Percentile:55.01(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency (JAEA) is the first to start the mass production of the TF conductors in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The height and width of the TF coils are 14 m and 9 m, respectively. The conductor is cable-in-conduit conductor (CICC) with a central spiral. A circular multistage superconducting cable is inserted into a circular stainless steel jacket with a thickness of 2 mm. A total of 900 Nb$$_{3}$$Sn strands and 522 copper strands are cabled around the central spiral and the cable is inserted into a round-in-round stainless steel jacket. It was observed that the cabling pitch of the destructive sample is longer than the original pitch at cabling. The JAEA carried out the tensile tests of the cable and the measurement of the cable rotation during the insertion to investigate the cause of the elongation. The cause of elongation was clarified and the results will be described in this paper.

Journal Articles

Analytical study of degradation of CIC conductor performance due to strand bending and buckling

Kajitani, Hideki; Hemmi, Tsutomu; Murakami, Haruyuki; Koizumi, Norikiyo

IEEE Transactions on Applied Superconductivity, 23(3), p.6001505_1 - 6001505_5, 2013/06

 Times Cited Count:5 Percentile:34.12(Engineering, Electrical & Electronic)

Critical current of cable-in-conduit conductors (CICCs) for ITER TF coils was measured. It was found from these test results that the measured critical current was lower than that evaluated from the critical current performance of a single strand. One of the explanations for this phenomenon is a non-uniform current distribution due to (1) unbalanced resistance among strands and between the strand and the upper/bottom joint and (2) local degradation of strand in the conductor. It is reported that the former was improved by using solder-filled joint but the latter issue seems to still remain. Therefore, the author developed a new analysis model for the calculation of strain distribution in the conductor taking account of strand bending and buckling and then, combined this with the electrical circuit model developed by authors before. Simulation results show that when local degradation is significant, the conductor performance can be degraded. In this presentation, these results are reported.

Journal Articles

Mass production of Nb$$_{3}$$Sn conductors for ITER toroidal field coils in Japan

Takahashi, Yoshikazu; Isono, Takaaki; Hamada, Kazuya; Nunoya, Yoshihiko; Nabara, Yoshihiro; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Koizumi, Norikiyo; Oshikiri, Masayuki; et al.

IEEE Transactions on Applied Superconductivity, 22(3), p.4801904_1 - 4801904_4, 2012/06

 Times Cited Count:7 Percentile:44.38(Engineering, Electrical & Electronic)

Japan Atomic Energy Agency is the first to start the mass production of the TF conductors in Phase IV in March 2010 among the 6 parties who are procuring TF conductors in the ITER project. The conductor is cable-in-conduit conductor with a central spiral. A total of 900 Nb$$_{3}$$Sn strands and 522 copper strands are cabled around the central spiral and then wrapped with stainless steel tape whose thickness is 0.1 mm. Approximately 60 tons of Nb$$_{3}$$Sn strands were manufactured by the two suppliers in December 2010. This amount corresponds to approximately 55% of the total contribution from Japan. Approximately 30% of the total contribution from Japan was completed as of February 2011. JAEA is manufacturing one conductor per month under a contract with two Japanese companies for strands, one company for cabling and one company for jacketing. This paper summarizes the technical developments including a high-level quality assurance. This progress is a significant step in the construction of the ITER machine.

Journal Articles

Analytical model of the critical current of a bent Nb$$_{3}$$Sn strand

Koizumi, Norikiyo; Murakami, Haruyuki; Hemmi, Tsutomu; Nakajima, Hideo

Superconductor Science and Technology, 24(5), p.055009_1 - 055009_12, 2011/05

 Times Cited Count:18 Percentile:63.38(Physics, Applied)

Critical current performance of a large Nb$$_{3}$$Sn cable-in-conduit conductor (CICC) was degraded by periodic bending of strands due to a large transverse electromagnetic force. The degradation of each strand due to this bending should be evaluated in calculations of the critical current of a CICC, but a suitable model has not been developed yet. Therefore, the authors have developed a new analytical model which takes into account plastic deformation of copper and bronze and filament breakage. Calculated results were compared with test results for uniformly bent Nb$$_{3}$$Sn bronze-route strands. Calculated results assuming a high-transverse resistance model (HTRM) show good agreement with the test results, a finding which confirms the validity of the model. Because of a much shorter calculation time than for numerical simulation, the developed model seems much more practical for use in calculating the critical current performance of a Nb$$_{3}$$Sn CICC. In addition, simulation results show that since the neutral axis of a bent strand shifts to the compressive side due to plastic deformation of the copper and bronze, and/or filament breakage, the strand is elongated by bending. This elongation may enhance the strand's critical current performance. Moreover, calculated results indicate that dependence of the critical current on the bending strain is affected by the bending history if the strand is excessively bent, especially when filaments are broken. In a real magnet, since a strand in a CICC is normally subject to the maximum electromagnetic force prior to an evaluation of its performance at a lower electromagnetic force, the effect of over-bending should be taken into account in calculations of its critical current performance, especially when filament breakage occurs.

Journal Articles

Growth of large protein crystals by a large-scale hanging-drop method

Kakinouchi, Keisuke*; Nakamura, Tsutomu*; Tamada, Taro; Adachi, Hiroaki*; Sugiyama, Shigeru*; Maruyama, Mihoko*; Takahashi, Yoshinori*; Takano, Kazufumi*; Murakami, Satoshi*; Inoue, Tsuyoshi*; et al.

Journal of Applied Crystallography, 43(4), p.937 - 939, 2010/08

 Times Cited Count:4 Percentile:50.4(Chemistry, Multidisciplinary)

A method for growing large protein crystals is described. In this method, a cut pipette tip is used to hang large-scale droplets (maximum volume 200 $$mu$$l) consisting of protein and precipitating agents. A crystal grows at the vapor-liquid interface; thereafter the grown crystal can be retrieved by droplet-droplet contact both for repeated macroseeding and for mounting crystals in a capillary. Crystallization experiments with peroxiredoxin of ${it Aeropyrum pernix}$ K1(thioredoxin peroxidase, ApTPx) and hen egg white lysozyme demonstrated that this large-scale hanging-drop method could produce a large-volume crystal very effectively. A neutron diffraction experiment confirmed that an ApTPx crystal (6.2 mm$$^{3}$$) obtained by this method diffracted to beyond 3.5 ${AA}$ resolution.

JAEA Reports

Design study on sodium-cooled reactor; Results of the studies in 2004 (Joint research)

Hishida, Masahiko; Murakami, Tsutomu*; Kisohara, Naoyuki; Fujii, Tadashi; Uchita, Masato*; Hayafune, Hiroki; Chikazawa, Yoshitaka; Usui, Shinichi; Ikeda, Hirotsugu; Uno, Osamu; et al.

JAEA-Research 2006-006, 125 Pages, 2006/03

JAEA-Research-2006-006.pdf:11.55MB

In Phase I of the "Feasibility Studies on Commercialized Fast Reactor Cycle Systems (F/S)", an advanced loop type reactor has been selected as a promising concept of sodium-cooled reactor, which has a possibility to fulfill the design requirements of the F/S. In Phase II, design improvement for further cost reduction and the establishment of the plant concept has been performed. In this study, reactor core design and large-scale plant design have been performed by adopting the modified fuel assembly with inner duct structure and double-wall straight tube steam generator (SG), which concepts were chosen at the interim review of FY 2003. For this SG, safety logics have been studied and the structural concept has been established. And the plant designs improving the in-service inspection (ISI) and repair capability have been performed. Furthermore, elaborate confirmation of the design has been performed reflecting the development of elemental technology, back-up concepts have been proposed. Besides, cost reduction measures have been studied by reducing reactor grade materials, introducing autonomous standardizations, simplifying the design due to deregulation and adopting systemized standards for BOP and NSSS. From now on, reflecting the results of elemental experiments, in-depth design studies and examination of critical issues will be carried out and the plant concept will accomplish in preparation for the final evaluation in Phase II.

Journal Articles

Progress on the plant design concept of sodium-cooled fast reactor

Hishida, Masahiko; Murakami, Tsutomu; Konomura, Mamoru; Toda, Mikio*

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 6 Pages, 2005/10

An innovative concept of sodium-cooled fast reactor, named JNC Sodium Cooled FR (JSFR) has been created and modified through the Feasibility Study on Commercialized FR Cycle System, aiming at full satisfaction of the development targets. A modified concept of JSFR applied double-wall straight tube type steam generator (SG) which is excelling in safety for sodium-water reaction has been developed. In addition, decay heat removal system suitable for the straight tube SG has been selected and in-service inspection and repair capabilities have been improved. As the result of this study, the potential to realize this plant concept has been obtained through evaluation concerning safety and economics.

Journal Articles

Field evidence for uranium nanocrystallization and its implications for uranium transport

Murakami, Takashi*; Sato, Tsutomu*; Onuki, Toshihiko; Isobe, Hiroshi*

Chemical Geology, 221(1-2), p.117 - 126, 2005/09

 Times Cited Count:53 Percentile:74.58(Geochemistry & Geophysics)

High-resolution transmission and scanning electron microscopies (HRTEM and SEM) both equipped with energy dispersive X-ray spectrometers (EDS) have been used to determine the chemical form of U(VI) in rocks and to examine U uptake mechanisms at low U concentrations (10$$^{8}$$$$sim$$10$$^{7}$$ mol/L) in the downgradient of the Koongarra U ore deposit in Australia. We found that uranyl-phosphate nanocrystallization, though initiated by adsorption, is a dominating mechanism of the U uptake and controls long-term U transport at low U concentrations.

JAEA Reports

Feasibility Study on Ultrasonic Flow Meter for Sodium-cooled FBR

Hishida, Masahiko; Murakami, Tsutomu; Konomura, Mamoru

JNC TN9400 2005-028, 71 Pages, 2005/06

JNC-TN9400-2005-028.pdf:4.8MB

In the "Feasibility Study on Commercialized Fast Reactor Cycle Systems", 12-chromium steel which has the magnetic property is adopted to the primary and secondary system piping of sodium-cooled reactor. Hence the studies on ultrasonic flow-meter for primary and secondary cooling system have been conducted. In this study, elementary tests in the air and in water were performed in order to select ultrasonic transducer and couplant which suit high temperature and exchange by remote control operation and to verify the ultrasonic propagation characteristic of the transducer and couplant (mainly sensitivity) and the measurement performance in large-scale pipe (mainly influence of attenuation of ultrasonic). Furthermore, for conducing to the setup of set points like "primary flow rate low" reactor trip signal detected by the ultrasonic flow-meter, the ultrasonic transducers for normal temperature were attached at the downstream in the elbow of the test facility which has been used for the water fluid and oscillation test for large diameter piping and fluctuation data from the ultrasonic transducers were acquired. The results are as follows: (1)As a result of investigating high temperature couplant, gold was selected since it was the most stable on all the temperature range containing high temperature among solid metal couplants and force required for the stability of the characteristic is expected to be small. (2)Signal level of ultrasonic transducer with the surface pressure of 1.45$$times$$10$$^{4}$$Pa (the force of 5kN) exceeds 50% of that with the couplant for normal temperature. In the transient temperature test, signal level of ultrasonic transducer became larger with a temperature rise and the fall of the signal level considered to originate in the fall of force was not appear. (3)S/N ratio of the signal exceeded 23dB in the elementaly test in water, and it was expected more than 18dB even if more attenuation of ultrasonic by the propagation longer distance ...

JAEA Reports

Design Study on Sodium-Cooled Large-Scale Reactor

Murakami, Tsutomu; Hishida, Masahiko; Kisohara, Naoyuki; Hayafune, Hiroki; Hori, Toru; Fujii, Tadashi; Uchita, Masato; Chikazawa, Yoshitaka; Uno, Osamu; Saigusa, Toshiie; et al.

JNC TY9400 2004-014, 78 Pages, 2004/07

JNC-TY9400-2004-014.pdf:7.97MB

This report summarizes the results of the design study on the sodium-cooled large-scale reactor performed in JFY2003, which is the third year of Phase 2. In the JFY2003 design study, critical subjects related to safety, structural integrity and thermal hydraulics which found in the last fiscal year has been examined and the plant concept has been modified. Furthermore, fundamental specifications of main systems and components have been set and economy has been evaluated. In addition, as the interim evaluation of the candidate concept of the FBR fuel cycle is to be conducted, cost effectiveness and achievability for the development goal were evaluated and the data of the three large-scale reactor candidate concepts were prepared.

JAEA Reports

Design Study on Sodium-Cooled Middle-Scale Modular Reactor

Hishida, Masahiko; Murakami, Tsutomu; Kisohara, Naoyuki; Fujii, Tadashi; Uchita, Masato; Hayafune, Hiroki; Chikazawa, Yoshitaka; Hori, Toru; Saigusa, Toshiie; Uno, Osamu; et al.

JNC TY9400 2004-012, 97 Pages, 2004/07

JNC-TY9400-2004-012.pdf:12.55MB

Based on the concept of a plant consisting of four modules with a capacity of 750 MWe each, which has been established by the end of FY2002, a concept of the entire plant was proposed, reflecting the modifications related to the high internal conversion type core, the double-wall straight tube steam generator (SG), and the fuel storage system. Concept studies were also performed to overcome the drawbacks of the sodium and to achieve in-service inspection and repair as easily as in light water reactor. Furthermore, feasibility studies were carried out to confirm the design, which included safety, thermal-hydraulics and the structures of the primary reactor auxiliary cooling system and the double-wall straight tube SG. A prospect for realization of this plant concept has been obtained through the evaluation results. In addition, as the interim evaluation of the candidate concepts of the FBR fuel cycle is to be conducted, cost effectiveness and achievability for the development goal were evaluated and the data of the three medium-scale reactor candidate concepts were prepared.

JAEA Reports

Feasibility Study on Commercialization of Fast Breeder Reactor Cycle Systems Interim Report of Phase II; Technical Study Report for Reactor Plant Systems

Konomura, Mamoru; Ogawa, Takashi; Okano, Yasushi; Yamaguchi, Hiroyuki; Murakami, Tsutomu; Takaki, Naoyuki; Nishiguchi, Youhei; Sugino, Kazuteru; Naganuma, Masayuki; Hishida, Masahiko; et al.

JNC TN9400 2004-035, 2071 Pages, 2004/06

JNC-TN9400-2004-035.pdf:76.42MB

The attractive concepts for Sodium-, lead-bismuth-, helium- and water-cooled FBRs have been created through using typical plant features and employing advanced technologies. Efforts on evaluating technological prospects of feasibility have been paid for these concepts. Also, it was comfirmed if these concepts satisfy design requierments of capability and performance presumed in the feasibilty study on commertialization of Fast Breeder Reactor Systems. As results, it was concluded that the selection of sodium-cooled reactor was most rational for practical use of FBR technologies in 2015.

Journal Articles

Crystal chemistry and microstructures of uranyl phosphates

*; Murakami, Takashi*; Kogure, Toshihiro*; Isobe, Hiroshi; Sato, Tsutomu

Mat. Res. Soc. Symp. Proc., 506, p.839 - 846, 1998/00

no abstracts in English

Journal Articles

Mobility of uranium during weathering

Murakami, Takashi*; Onuki, Toshihiko; Isobe, Hiroshi; Sato, Tsutomu

American Mineralogist, 82, p.888 - 899, 1997/00

no abstracts in English

Journal Articles

Iron nodules scavenging uranium from groundwater

Sato, Tsutomu; Murakami, Takashi*; Yanase, Nobuyuki; Isobe, Hiroshi; T.E.Payne*; P.L.Airey*

Environmental Science & Technology, 31(10), p.2854 - 2858, 1997/00

 Times Cited Count:77 Percentile:88.6(Engineering, Environmental)

no abstracts in English

33 (Records 1-20 displayed on this page)