Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Shikama, Tatsuo*; Knitter, R.*; Konys, J.*; Muroga, Takeo*; Tsuchiya, Kunihiko; M
slang, A.*; Kawamura, Hiroshi; Nagata, Shinji*
Fusion Engineering and Design, 83(7-9), p.976 - 982, 2008/12
Times Cited Count：40 Percentile：90.41(Nuclear Science & Technology)Functional materials should play an important role not only in ITER but also in fusion machines beyond ITER, though it is occasionally claimed that future fusion plants should have much more simple structures and they should be free from auxiliary systems such as diagnostics. Studies on test blanket modules (TBM) clearly show the importance of functional materials there. The paper will review the present status of studies and developments of functional ceramics for nuclear fusion applications, with a perspective on their application in electric-power generating fusion power plant, namely DEMO.
Ogawa, Hiroaki; Sugie, Tatsuo; Kasai, Satoshi*; Katsunuma, Atsushi*; Hara, Hirotsugu*; Takeyama, Norihide*; Kusama, Yoshinori
Fusion Engineering and Design, 83(10-12), p.1405 - 1409, 2008/12
Times Cited Count：16 Percentile：69.33(Nuclear Science & Technology)no abstracts in English
Nakahira, Masataka; Takeda, Nobukazu; Kakudate, Satoshi; Onozuka, Masanori*
Fusion Engineering and Design, 83(10-12), p.1578 - 1582, 2008/12
Times Cited Count：5 Percentile：33.82(Nuclear Science & Technology)The structure and fabrication methods of the ITER vacuum vessel have been investigated and defined by the ITER international team. However, some of the current specifications are very difficult to be achieved from the manufacturing point of view and will lead to cost increase. This report summarizes the Japanese proposed specification of the VV mock-up describing differences between the ITER supplied design. A series of the fabrication and assembly procedures for the mock-up are presented in this report, together with candidates of welding configurations. Finally, the report summarizes the results of mock-up fabrication, including results of non-destructive examination of weld lines, obtained welding deformation and issues revealed from the fabrication experience.
Iwai, Yasunori; Hiroki, Akihiro; Yagi, Toshiaki*; Tamada, Masao; Yamanishi, Toshihiko
Fusion Engineering and Design, 83(10-12), p.1410 - 1413, 2008/12
Times Cited Count：7 Percentile：43.42(Nuclear Science & Technology)The radiation durability of the solid-polymer-electrolyte (SPE) water electrolyzer composed of the Water Detritiation System (WDS) was investigated. A series of 
-ray and electron beam irradiation tests of Nafion N117 ion exchange membrane, a key polymer in a SPE electrolyzer, beyond ITER-WDS requirement (530kGy) indicated Nafion N117 has enough radiation durability up to 1600 kGy from the view points of mechanical strength and ion exchange capacity. To keep electrolysis function of a SPE cell up to 530 kGy, we suggest replacing Teflon with polyimide. A series of -ray irradiation test of Kapton polyimide observed no serious damage in strength up to 1500 kGy. Concerning rubber material for O-ring seal, we observed that soaking VITON rubber keeps the constant value of tensile strength up to 1500 kGy. Moreover organic elution was not observed from a soak of VITON. From the viewpoint of stable strength and organic elution, VITON is a first candidate for rubber material.
Takeda, Nobukazu; Kakudate, Satoshi; Nakahira, Masataka; Shibanuma, Kiyoshi; Tesini, A.*
Fusion Engineering and Design, 83(10-12), p.1837 - 1840, 2008/12
Times Cited Count：14 Percentile：65.44(Nuclear Science & Technology)The maintenance activity in the ITER has to be performed remotely because 14 MeV neutron caused by fusion reaction induces activation of structural material and emission of ray. In general, it is one of the most critical issues to avoid collision between the remote maintenance system and in-vessel components. Therefore, the visual information in the vacuum vessel is required strongly to understand arrangement of these devices and components. However, there is a limitation of arrangement of viewing cameras in the vessel because of high intensity of ray. Furthermore, visibility of the interested area such as the contacting part is frequently disturbed by the devices and components, thus it is difficult to recognize relative position between the devices and components only by visual information even if enough cameras and lights are equipped. From these reasons, the simulator to recognize the positions of each devices and components is indispensable for remote handling systems in fusion reactors. The authors have been developed a simulator for the remote maintenance system of the ITER blanket using a general 3D robot simulation software "ENVISION". The simulator is connected to the control system of the manipulator which was developed as a part of the blanket maintenance system in the EDA and can reconstruct the positions of the manipulator and the blanket module using the position data of the motors through the LAN. In addition, it can provide virtual visual information, such as the connecting operation behind the blanket module with making the module transparent on the screen. It can be used also for checking the maintenance sequence before the actual operation.
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：20 Percentile：76.19(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
. 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.
Asai, Keisuke*; Yukawa, Kyohei*; Iguchi, Tetsuo*; Naoi, Norihiro*; Watanabe, Kenichi*; Kawarabayashi, Jun*; Yamauchi, Michinori*; Konno, Chikara
Fusion Engineering and Design, 83(10-12), p.1818 - 1821, 2008/12
Times Cited Count：0 Percentile：0.00(Nuclear Science & Technology)The fuel ratio in a DT burning plasma can be derived from the intensity ratio of DD/DT neutrons, and detecting a trace of DD neutrons in the DT burning plasma is a key issue. A new type of neutron spectrometer is proposed to monitor the fuel ratio in the core of the ITER plasma. The system based on a conventional time-of-flight method consists of a water cell as a neutron scattering material and tens of scintillator pairs arranged around the first scintillator in a corn shape. We call it a multi-scattering time-of-flight neutron spectrometer (MS-TOF). A trial experiment was conducted for the prototype MS-TOF system with a DT neutron beam (20-mm diameter) at the Fusion Neutronics Source (FNS), Japan Atomic Energy Agency. The experimental results show that the DD and DT neutron peaks are clearly observed, and the experiment has successfully demonstrated the feasibility of the MS-TOF concept for detecting trace-DD neutrons within a DT neutron beam extracted from a DT burn plasma.
Shu, Wataru; Isobe, Kanetsugu; Yamanishi, Toshihiko
Fusion Engineering and Design, 83(7-9), p.1044 - 1048, 2008/12
Times Cited Count：47 Percentile：92.76(Nuclear Science & Technology)At 315 K, only sparse low-dome blisters appeared even the fluence was increased to 10
D/m. At around 400 K, the blisters became much denser and the dome of blisters became a little higher. Peculiar change occurred around 500 K, where two kinds of blisters appeared. One is the large blisters with sizes of a few tens of microns and varying ratios of height against chord (up to 0.6), and the other is the small blisters with chords of less than a few microns and large ratio of height against chord (about 0.7). In high temperature region (higher than 600 K), the blisters became much sparser with the increasing temperature and disappeared at 1000 K. Deuterium retention showed the maximum around 500 K, corresponding to the appearance of two kinds of high-dome blisters.
Kakudate, Satoshi; Takeda, Nobukazu; Nakahira, Masataka; Matsumoto, Yasuhiro; Shibanuma, Kiyoshi; Tesini, A.*
Fusion Engineering and Design, 83(10-12), p.1850 - 1855, 2008/12
Times Cited Count：13 Percentile：62.87(Nuclear Science & Technology)The design of in-vessel transporter (IVT) including vehicle manipulator has been updated according to the design changes such as blanket segmentation and structure, taking account of the interface between modules and vehicle manipulator. In particular, the updated design of the vehicle manipulator and rail has been carried out in order to avoid the interference between modules and vehicle manipulator. According to the updated design, the vehicle manipulator has been reduced by about 30%, compared with the reference design. In parallel with design activities, the R&D to clarify the specifications of the IVT design in detail is also performed, i.e., simulation system to provide the visual information during maintenance, dry lubricant to prevent the lubricant oil from spreading in the VV. The rail connection and cable handling in the transfer cask, which are critical issues for IVT system, are under preparation of the demonstration tests to finalize the design of the IVT system. Connection of the rail joint and cable handling test facilities are planned and under fabrication now. These test facility will be installed by the end of March 2008, and the performance tests will be carried out from April 2008.
El-Guebaly, L. A.*; Massaut, V.*; Tobita, Kenji; Cadwallader, L.*
Fusion Engineering and Design, 83(7-9), p.928 - 935, 2008/12
Times Cited Count：26 Percentile：82.39(Nuclear Science & Technology)After decades of designing fusion power plants, it is timely to develop a new framework for managing the activated materials that will be generated during plant operation and after decommissioning. This will clearly demonstrate that scientists developing fusion processes and facilities will be dealing with the back end from the beginning of the conceptual design of power plants. It is becoming evident that future regulations for geological burial will be upgraded to assure tighter environmental controls. Beginning in the mid 1980s and continuing to the present, numerous fusion designs examined replacing the disposal option with more environmentally attractive approaches, redirecting their attention to recycling and clearance while continuing the development of materials with low activation potential.
Kawashima, Hisato; Shimizu, Katsuhiro; Takizuka, Tomonori; Asakura, Nobuyuki; Sakurai, Shinji; Matsukawa, Makoto; Fujita, Takaaki
Fusion Engineering and Design, 83(10-12), p.1643 - 1647, 2008/12
Times Cited Count：18 Percentile：72.94(Nuclear Science & Technology)no abstracts in English
Tanaka, Satoru*; Takatsu, Hideyuki
Fusion Engineering and Design, 83(7-9), p.865 - 869, 2008/12
Times Cited Count：14 Percentile：65.44(Nuclear Science & Technology)The world fusion community is now launching construction of ITER. In parallel with the ITER Program, Broader Approach activities also started this year by the collaboration of Japan and EURATOM. The Atomic Energy Commission of Japan reviewed the on-going Third Phase Basic Program of Fusion Research and Development, and then issued the Report in November 2005. This report presented a roadmap toward the DEMO and beyond and identified research and development items on fusion nuclear technology indispensable for fusion energy utilization. In the present paper, Japanese view and policy on ITER and beyond will be summarized mainly from the viewpoints of fusion nuclear technology, and a minimum set of research and development items on fusion nuclear technology toward DEMO and essential for fusion energy utilization are overviewed.
Konishi, Satoshi*; Glugla, M.*; Hayashi, Takumi
Fusion Engineering and Design, 83(7-9), p.954 - 958, 2008/12
Times Cited Count：19 Percentile：74.63(Nuclear Science & Technology)Murdoch, D.*; Glugla, M.*; Hayashi, Takumi; Perevesentsev, A.*; Stephan, Y.*; Taylor, C.*
Fusion Engineering and Design, 83(10-12), p.1355 - 1358, 2008/12
Times Cited Count：11 Percentile：57.45(Nuclear Science & Technology)Nakamichi, Masaru; Ishitsuka, Etsuo; Shimakawa, Satoshi; Kan, Satoshi*
Fusion Engineering and Design, 83(7-9), p.1321 - 1325, 2008/12
Times Cited Count：2 Percentile：16.35(Nuclear Science & Technology)no abstracts in English
Ioki, Kimihiro*; Barabash, V.*; Cordier, J.*; Enoeda, Mikio; Federici, G.*; Kim, B. C.*; Mazul, I.*; Merola, M.*; Morimoto, Masaaki*; Nakahira, Masataka*; et al.
Fusion Engineering and Design, 83(7-9), p.787 - 794, 2008/12
Times Cited Count：20 Percentile：76.19(Nuclear Science & Technology)This paper presents recent results of ITER activities on Vacuum Vessel (VV), blanket, limiter, and divertor. Major results can be summarized as follows. (1) The VV design is being developed in more details considering manufacturing and assembly methods, and cost. Incorporating manufacturing studies being performed in cooperation with parties, the regular VV sector design has been nearly finalized. (2) The procurement allocation of blanket modules among 6 parties was fixed and the blanket module design has progressed in cooperation with parties. Fabrication of mock-ups for prequalification testing is under way and the tests will be performed in 2007-2008. (3) The divertor activities have progressed with the aim of launching the procurement according to the ITER project schedule.
Konno, Chikara; Ochiai, Kentaro; Wada, Masayuki*; Sato, Satoshi
Fusion Engineering and Design, 83(10-12), p.1774 - 1781, 2008/12
Times Cited Count：14 Percentile：65.44(Nuclear Science & Technology)Many integral benchmark experiments with DT neutrons have been carried out for nuclear data verification for fusion nuclear design at JAEA FNS; simple benchmark experiments, time-of-flight, breeding blanket experiments. For a few years several nuclear data libraries have been newly released; JENDL-3.3, FENDL-2.1, JEFF-3.1 and ENDF/B-VII.0. It is essential to verify these libraries through analyses of integral benchmark experiments. Thus we carried out a series of analyses for the benchmark experiments at JAEA FNS with FENDL-2.1, JENDL-3.3, JEFF-3.1 and ENDF/B-VII.0. The Monte Carlo code MCNP-4C was used for this analysis. Calculated results were compared with measured ones. They were also compared each other. The calculated results with FENDL-2.1, JENDL-3.3, JEFF-3.1 and ENDF/B-VII.0 were almost the same and represented the measured ones except for some experiments.
Hirose, Takanori; Enoeda, Mikio; Ogiwara, Hiroyuki; Tanigawa, Hiroyasu; Akiba, Masato
Fusion Engineering and Design, 83(7-9), p.1176 - 1180, 2008/12
Times Cited Count：16 Percentile：69.33(Nuclear Science & Technology)This paper summarize the fabrication process of the first wall structure and provides the material properties of the structural material F82H and dimensional stability of the components through whole of the process. A cold-rolling process introduced typical stretched rolling structure and ferrite/martensite dual phase structure, which lead reduction in strength. These anisotropic microstructural features were successfully recovered by optimized HIP process at 1373 K. As for dimensional stability of the components, a full-scale mockup has been developed with F82H tubes and plates. The HIPped mockup demonstrated good accordance with a design drawing. The dimensions of wall thickness and cooling channels were to size even after HIP. According to these results, the fabrication process does not degrade the material properties and demonstrates good dimensional accuracy and stability of the FW structure.
Ochiai, Kentaro; Sato, Satoshi; Wada, Masayuki*; Iida, Hiromasa; Takakura, Kosuke; Kutsukake, Chuzo; Tanaka, Shigeru; Abe, Yuichi; Konno, Chikara
Fusion Engineering and Design, 83(10-12), p.1725 - 1728, 2008/12
Times Cited Count：1 Percentile：9.70(Nuclear Science & Technology)Under the ITER/ITA task, we have conducted the neutron streaming experiment simulating narrow and deep gaps at boundaries between ITER vacuum vessel and equatorial port plugs. Micro fission chambers and some activation foils were utilized to measure fission rates and reaction rates to evaluate the relative fast and slow neutron fluences along the gap in the experimental assembly. The MCNP4C, TORT and Attila codes were used for the experimental analysis. From comparing our measurements and calculations, the following facts were found: (1) In case of a such narrow and deep gap structure, the calculation with MCNP, TORT and ATTILA codes and FENDL-2.1 is sufficient to predict fast neutron field inside the gap.: (2) Angular quadrature set of upward biased U315 and last collided source calculation on TORT and Attila were very important technique for accurate estimation of neutron transport.
Tsuru, Daigo; Enoeda, Mikio; Akiba, Masato
Fusion Engineering and Design, 83(7-9), p.1238 - 1243, 2008/12
Times Cited Count：6 Percentile：38.79(Nuclear Science & Technology)One-dimensional analyses are carried out for the three representative event sequences about heatup of WCSB TBM. For the event sequence of loss of cooling of the TBM during plasma operation, the requirement to the TBM design becomes apparent that no cooling pipe rupture can be guaranteed under the predicted highest temperature condition to prevent the activation of the Be-H
O chemical reaction under the high temperature condition. For the event sequence of ingress of coolant into the TBM during plasma operation, the requirement for the cooling system of TBM becomes apparent that the cooling system for the TBM should be designed to continue its operation against partial loss of coolant due to the ingress of coolant. For the loss of off-site power after the ingress of coolant, it is confirmed that the event converges.
