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Journal Articles

Validation of welding technology for ITER TF coil structures

Chida, Yutaka; Iguchi, Masahide; Takano, Katsutoshi; Nakajima, Hideo; Osemochi, Koichi*; Niimi, Kenichiro*; Tokai, Daisuke*; Gallix, R.*

Fusion Engineering and Design, 86(12), p.2900 - 2903, 2011/12

 Times Cited Count:10 Percentile:62.85(Nuclear Science & Technology)

TF coil structures, which support large electromagnetic force generated in TF coils under the cryogenic temperature (about 4K), are the mega welding structures composed of coil case and support structures made of high strength and high toughness stainless steel. JAEA started the study on welding trials for heavy thickness materials since 2008 and is planning of full scale mock-up model fabrication for main sub-components (1 set of inboard side and 1set of outboard side) in 2010 in order to investigate the technical issues for manufacturing of TF coil structures. This paper introduces the results on welding trials and status of full scale mock-up model fabrication to confirm the validity of welding technology and manufacturing design before fabricating actual products.

Journal Articles

Japanese contribution to the DEMO-R&D program under the Broader Approach activities

Nishitani, Takeo; Yamanishi, Toshihiko; Tanigawa, Hiroyasu; Nozawa, Takashi; Nakamichi, Masaru; Hoshino, Tsuyoshi; Koyama, Akira*; Kimura, Akihiko*; Hinoki, Tatsuya*; Shikama, Tatsuo*

Fusion Engineering and Design, 86(12), p.2924 - 2927, 2011/12

 Times Cited Count:6 Percentile:46.07(Nuclear Science & Technology)

Several technical R&D activities related to the blanket materials are newly launched as a part of the Broader Approach (BA) activities, which was initiated by the EU and Japan. According to the common interests of these parties for DEMO, R&Ds on reduced activation ferritic/martensitic (RAFM) steels as structural material, SiCf/SiC composites as a flow channel insert material and/or alternative structural material, advanced tritium breeders and neutron multipliers, and tritium technology are carried out through the BA DEMO R&D program, in order to establish the technical bases on the blanket materials and the tritium technology required for DEMO design. This paper describes overall schedule of those R&D activities and recent progress in Japan carried out by JAEA as the domestic implementing agency on BA, collaborating with Japanese universities and other research institutes.

Journal Articles

Basic design guideline for the preliminary engineering design of PIE facilities in IFMIF/EVEDA

Kogawara, Takafumi; Wakai, Eiichi; Kikuchi, Takayuki; Yamamoto, Michiyoshi; Molla, J.*

Fusion Engineering and Design, 86(12), p.2904 - 2907, 2011/12

 Times Cited Count:3 Percentile:26.98(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Long-term properties of reduced activation ferritic/martensitic steels for fusion reactor blanket system

Shiba, Kiyoyuki; Tanigawa, Hiroyasu; Hirose, Takanori; Sakasegawa, Hideo; Jitsukawa, Shiro

Fusion Engineering and Design, 86(12), p.2895 - 2899, 2011/12

 Times Cited Count:38 Percentile:94.08(Nuclear Science & Technology)

Aging properties of reduced activation ferritic/martensitic steel F82H was researched at temperature ranging from 400$$^{circ}$$C to 650$$^{circ}$$C up to 100,000 hr. Microstructure, tensile, and Charpy properties were carried out. Laves was found at temperatures between 550 and 650$$^{circ}$$C and M$$_{6}$$C carbides were found at the temperatures between 500 and 600$$^{circ}$$C over 10,000 hr. These precipitates caused degradation in toughness, especially at temperatures ranging from 550$$^{circ}$$C to 650$$^{circ}$$C. Tensile properties do not have serious aging effect, except for 650$$^{circ}$$C, which caused large softening even after 10.000 hr. Increase of precipitates also causes some degradation in ductility, but it is not critical. Large increase in DBTT caused by the large Laves phase precipitation at grain boundary was observed in the 650$$^{circ}$$C aging. Laves precipitates at grain boundary also degrades the USE of the aged materials. These aging test results provide F82H can be used up to 30,000 hr at 550$$^{circ}$$C.

Journal Articles

Simplification of blanket system for SlimCS fusion DEMO reactor

Someya, Yoji; Takase, Haruhiko; Uto, Hiroyasu; Tobita, Kenji; Liu, C.; Asakura, Nobuyuki

Fusion Engineering and Design, 86(9-11), p.2269 - 2272, 2011/11

 Times Cited Count:28 Percentile:89.78(Nuclear Science & Technology)

Conceptual design of a tritium-breeding blanket for SlimCS has been studied. The blanket structure with neutron multiplier Be-plate was designed to be as thin as possible with keeping high Tritium Breeding Ratio (TBR). However, a structure of the blanket is complexity and the manufacture of the blanket is difficult from the viewpoint of engineering. Therefore, simplification of blanket structure is necessary for SlimCS. In this paper, we propose a simple blanket structure without decreasing the net TBR below 1.05. The proposed blanket structure is mixed Li$$_{4}$$SiO$$_{4}$$ pebbles or Li$$_{2}$$O pebbles for the tritium breeding and Be$$_{12}$$Ti pebbles for the neutron multiplication and these pebbles are filled in the blanket. ANIHEAT code with the nuclear data library FENDL-2.0 was used for the calculations of the neutronics and thermal analyses. As a result, it is shown that Li$$_{2}$$O pebbles blanket mixed with Be$$_{12}$$Ti pebbles is the most effective and the TBR is greater than 1.05.

Journal Articles

First qualification of ITER toroidal field coil conductor jacketing

Hamada, Kazuya; Takahashi, Yoshikazu; Isono, Takaaki; Nunoya, Yoshihiko; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Tsutsumi, Fumiaki; Koizumi, Norikiyo; Nakajima, Hideo; et al.

Fusion Engineering and Design, 86(6-8), p.1506 - 1510, 2011/10

 Times Cited Count:11 Percentile:62.85(Nuclear Science & Technology)

Japan Atomic Energy Agency has a responsibility for procurement of the ITER toroidal field coil conductors as Japanese Domestic Agency (JADA) of the ITER project. The TF conductor is a circular shaped cable-in-conduit conductor, which is composed of cable and stainless steel conduit (jacket). The outer diameter and wall thickness of jacket are 43.7mm and 2mm, respectively. The cable consists of 900 Nb$$_{3}$$Sn superconducting strands and 522 Cu strands. The length of TF conductor is 780m in maximum. Preparation of conductor fabrication was completed in December 2009. And then, to demonstrate a conductor manufacturing procedure, JADA fabricated 780m-long Cu dummy conductor as a process qualification. Finally, the 780m-long Cu dummy conductor has been successfully completed, ahead of other domestic agencies that are in charge of TF conductor procurement. Since all of manufacturing processes have been qualified, JADA started to fabricate superconducting conductors for TF coils.

Journal Articles

Progress of mock-up trials for ITER TF coil procurement in Japan

Matsui, Kunihiro; Koizumi, Norikiyo; Hemmi, Tsutomu; Takano, Katsutoshi; Nakajima, Hideo; Osemochi, Koichi*; Savary, F.*

Fusion Engineering and Design, 86(6-8), p.1531 - 1536, 2011/10

 Times Cited Count:2 Percentile:19.17(Nuclear Science & Technology)

The magnet system for ITER comprises 18 Toroidal Field (TF) Coils using Nb$$_{3}$$Sn cable-in-conduit superconductor, which operate at 4.5 K in supercritical helium. Japan Atomic Energy Agency (JAEA) is responsible for the procurement of 9 TF coils as Japanese Domestic Agency (JADA). Before launching the procurement of these coils, reduced and full-scale trials will be performed to determine and optimize the manufacturing process of a TF coil. During the manufacture of the TF coil, heat-treated superconducting cable-in-conduit conductor, whose length may vary during heat treatment, shall be inserted in the grooves of the radial plate (RP), which is part of the mechanical structure supporting the large electromagnetic forces that are of the order of 800 kN/m. The RP also enhance reliability of the electrical insulation that will be tested up to 19 kV DC and 2.5 kV AC for the winding pack to ground. Very accurate tolerances, of the order of 0.01% on the length of the RP grooves and of the wound conductor, are required to enable the insertion of the conductor. Therefore, the development of suitable manufacturing techniques for the RP and for the winding operation is essential to achieve this requirement. JAEA has contracted companies for fabrication trials of a full-scale RP and winding trials of a one-third scale double pancake to verify feasibility of the required tolerances from an industrial view point. Prior to these trials, JAEA developed a preliminary manufacturing plan and then, industry will carry out small-scale trials to demonstrate applicability of the preliminary manufacturing plan before making the reduced and full-scale trials. The small scale trials will include the cover plate welding with the laser welding, the impregnation using the acryl and metal models, and, the mechanical test and the trail bending of the TF conductor. The results of the small-scale trials and progress on the reduced and full-scale trials are presented in this paper.

Journal Articles

Progress in ECRF antenna development for JT-60SA

Kobayashi, Takayuki; Isayama, Akihiko; Hasegawa, Koichi; Suzuki, Sadaaki; Hiranai, Shinichi; Sato, Fumiaki; Wada, Kenji; Yokokura, Kenji; Shimono, Mitsugu; Sawahata, Masayuki; et al.

Fusion Engineering and Design, 86(6-8), p.763 - 767, 2011/10

 Times Cited Count:6 Percentile:46.07(Nuclear Science & Technology)

Progress of antenna development of the Electron Cyclotron Range of Frequency system for JT-60 SA is presented. Capability of pulse length of 100 s, which requires active cooling for mirrors, and flexibility of beam injection angles in both poloidal and toroidal directions are required for the antenna with high reliability. Mechanical and structural design works of the launcher (antenna and its support with steering structure) based on a linear motion antenna concept are in progress. The key component is a long-stroke bellows which enables to alter poloidal injection angle and a bellows which enables to alter toroidal injection angle. Using a newly fabricated mock-up of the steering structure, it was confirmed that the antenna was mechanically realized for poloidal and toroidal injection angle ranges of -10 to +45$$^{circ}$$ and -15 to +15$$^{circ}$$, respectively. Those angles are consistent with angles required in JT-60SA. The results of thermal and structural analyses are also presented.

Journal Articles

Development of high power long-pulse RF transmitter for ICRF heating in fusion researches and cyclotron accelerator

Kwak, J. G.*; Wang, S. J.*; Bae, Y. D.*; Kim, S. H.*; Hwang, C. K.*; Moriyama, Shinichi

Fusion Engineering and Design, 86(6-8), p.938 - 941, 2011/10

 Times Cited Count:1 Percentile:11.07(Nuclear Science & Technology)

KAERI have been developing the transmitters for ICRF heating for KSTAR and the cyclotron accelerator since 1996. The toroidal magnetic field of KSTAR is nominally 3 T so that 25-60 MHz transmitter is required to cover ICRF heating scenarios of the KSTAR. The first transmitter is operating up to 60 MHz and it succeeded in achieving 2 MW for 300 s in 2008. Up to 300 kW RF power was successfully injected to KSTAR plasmas. The second one is 70 kW/CW transmitter used for the cyclotron accelerator and their frequency range is from 25 to 50 MHz. Its engineering design was finished. The third one is 1 MW/VHF transmitter which was loaned from JAEA. As the operating ICRF frequency of KSTAR is lower, its cavity structure will be modified from 110 MHz to 60 MHz. The test results of 60 MHz and lessons from the high power test of 2 MW transmitter will be introduced and the circuit analysis and engineering design work for the second and third amplifiers will be shown.

Journal Articles

Trial fabrication of beryllides as advanced neutron multiplier

Nakamichi, Masaru; Yonehara, Kazuo; Wakai, Daisuke

Fusion Engineering and Design, 86(9-11), p.2262 - 2264, 2011/10

 Times Cited Count:22 Percentile:84.12(Nuclear Science & Technology)

Journal Articles

High-efficiency technology for lithium isotope separation using an ionic-liquid impregnated organic membrane

Hoshino, Tsuyoshi; Terai, Takayuki*

Fusion Engineering and Design, 86(9-11), p.2168 - 2171, 2011/10

 Times Cited Count:53 Percentile:96.84(Nuclear Science & Technology)

The tritium needed as a fuel for fusion reactors is produced by the neutron capture reaction of lithium-6 ($$^{6}$$Li) in tritium breeding materials. However, natural Li contains only about 7.6 at.% $$^{6}$$Li. In Japan, new lithium isotope separation technique using ionic-liquid impregnated organic membranes have been developed. The improvement in the durability of the ionic-liquid impregnated organic membrane is one of the main issues for stable, long-term operation of electrodialysis cells while maintaining good performance. Therefore, we developed highly-durable ionic-liquid impregnated organic membrane. Both ends of the ionic-liquid impregnated organic membrane were covered by a nafion 324 overcoat to prevent the outflow of the ionic liquid. The transmission of Lithium aqueous solution after 10 hours under the highly-durable ionic-liquid impregnated organic membrane is almost 13%. So this highly-durable ionic-liquid impregnated organic membrane for long operating of electrodialysis cells has been developed through successful prevention of ion liquid dissolution.

Journal Articles

Trial fabrication tests of advanced tritium breeder pebbles using sol-gel method

Hoshino, Tsuyoshi; Oikawa, Fumiaki

Fusion Engineering and Design, 86(9-11), p.2172 - 2175, 2011/10

 Times Cited Count:34 Percentile:92.76(Nuclear Science & Technology)

Lithium titanate (Li$$_{2}$$TiO$$_{3}$$) is one of the most promising candidates among tritium breeding materials because of its good tritium release characteristics. However, the mass of Li$$_{2}$$TiO$$_{3}$$ decreased with time in a hydrogen atmosphere by Li evaporation and with Li burn up. In order to prevent the mass decrease at high temperatures, Li$$_{2}$$TiO$$_{3}$$ with added Li have been developed as one of advanced tritium breeders. We have been promoting the development of fabrication technique of Li$$_{2}$$TiO$$_{3}$$ pebbles by the sol-gel method. The fabrication techniques of advanced tritium breeder pebbles have not been established for large quantities. Therefore, trial fabrication tests of advanced breeder pebbles were carried out using previous sol-gel method. The diameter of the pebbles is 1.18 mm, and the sphericity is 1.04. It is expected that an advanced tritium breeder with added Li will be stable under operating conditions, namely in a neutron environment at a high temperatures. Thus, these results show that the pebble fabrication using the sol-gel method is a promising production technique for mass production of the advanced tritium breeder pebbles.

Journal Articles

Present status of Japanese tasks for lithium target facility under IFMIF/EVEDA

Nakamura, Kazuyuki; Furukawa, Tomohiro; Hirakawa, Yasushi; Kanemura, Takuji; Kondo, Hiroo; Ida, Mizuho; Niitsuma, Shigeto; Otaka, Masahiko; Watanabe, Kazuyoshi; Horiike, Hiroshi*; et al.

Fusion Engineering and Design, 86(9-11), p.2491 - 2494, 2011/10

 Times Cited Count:10 Percentile:62.85(Nuclear Science & Technology)

In IFMIF/EVEDA, tasks for lithium target system are shared to 5 validation tasks (LF1-5) and a design task (LF6). The purpose of LF1 task is to construct and operate the EVEDA lithium test loop, and JAEA has a main responsibility to the performance of the Li test loop. LF2 is a task for the diagnostics of the Li test loop and IFMIF design. Basic research for the diagnostics equipment has been completed, and the construction for the Li test loop will be finished before March in 2011. LF4 is a task for the purification systems with nitrogen and hydrogen. Basic research for the purification equipment has been completed, and the construction of the nitrogen system for the Li test loop will be finished before March in 2011. LF5 is a task for the remote handling system with the target assembly. JAEA has an idea to use the laser beam for cutting and welding of the lip part of the flanges. LF6 is a task for the design of the IFMIF based on the validation experiments of LF1-5.

Journal Articles

Development of Pt/ASDBC catalyst for room temperature recombiner of atmosphere detritiation system

Iwai, Yasunori; Sato, Katsumi; Yamanishi, Toshihiko

Fusion Engineering and Design, 86(9-11), p.2164 - 2167, 2011/10

 Times Cited Count:14 Percentile:69.17(Nuclear Science & Technology)

We have developed the hydrophobic Pt catalysts applicable for tritium oxidation in the presence of saturated water vapor at room temperature. A new type of hydrophobic catalyst, Pt/ASDBC, has been prepared by dipositing platinum on alkyl-styrene diviyl-benzene copolymer (ASDBC). Pt/ASDBC is more hydrophobic than Pt/SDBC that is a promising catalyst for the water detritiation system. The deposited platinum used to prepare Pt/ASDBC catalyst was 1.0 g/L. The value was approximately half of a commercial Japanese Pt/SDBC catalyst. Tritium oxidation tests of the catalysts using 3 GBq/m$$^{3}$$ of tritium were performed in the absence/presence of saturated water vapor at room temperature. Tritium oxidation sufficient for room temperature recombiner was demonstrated using Pt/ASDBC catalyst.

Journal Articles

Fabrication and tests of EF conductors for JT-60SA

Kizu, Kaname; Kashiwa, Yoshitoshi; Murakami, Haruyuki; Obana, Tetsuhiro*; Takahata, Kazuya*; Tsuchiya, Katsuhiko; Yoshida, Kiyoshi; Hamaguchi, Shinji*; Matsui, Kunihiro; Nakamura, Kazuya*; et al.

Fusion Engineering and Design, 86(6-8), p.1432 - 1435, 2011/10

 Times Cited Count:8 Percentile:55.43(Nuclear Science & Technology)

In JT-60SA, central solenoid (CS) and plasma equilibrium field (EF) coils are procured by Japan. EF coil conductors are NbTi cable-in-conduit (CIC) conductor. Delivered superconducting cables and jackets are fabricated into CIC conductors at the jacketing facility with the length of 680 m constructed in the Naka site of JAEA. The production of superconductors with 444 m in length for actual EF coils was started from March 2010. The measurements of superconducting performance like current sharing temperature (Tcs) were conducted prior to the mass production. The measured Tcs was agreed with the expectation values from strand values indicating that no degradation was happened by production process.

Journal Articles

Wave period of free-surface waves on high-speed liquid lithium jet for IFMIF target

Kanemura, Takuji; Sugiura, Hirokazu*; Yamaoka, Nobuo*; Suzuki, Sachiko*; Kondo, Hiroo; Ida, Mizuho; Matsushita, Izuru*; Horiike, Hiroshi*

Fusion Engineering and Design, 86(9-11), p.2462 - 2465, 2011/10

 Times Cited Count:5 Percentile:40.36(Nuclear Science & Technology)

Wave period of free-surface waves on a high-speed liquid lithium (Li) jet is very important wave characteristics to investigate for validation of a Li target of the International Fusion Materials Irradiation Facility (IFMIF). In this paper, we report characteristics of wave period measured by a contact-type liquid level sensor. The experiments were conducted at a Li loop in Osaka University. In this loop, a plane Li jet simulating the IFMIF Li target can be controlled at the velocities of up to 15 m/s. Probability density distribution of the measured wave periods was nearly equal to the log-normal distribution. The fact that the wave period distribution is nearly equal to the log-normal distribution has been already identified in the ocean waves which are known for its random property. From present and previous our experimental results, it was concluded that random wave property developed for the ocean waves can apply to the free-surface waves on the Li jet.

Journal Articles

Safety concept of the IFMIF/EVEDA lithium test loop

Furukawa, Tomohiro; Kondo, Hiroo; Hirakawa, Yasushi; Kato, Shoichi; Matsushita, Izuru*; Ida, Mizuho; Nakamura, Kazuyuki

Fusion Engineering and Design, 86(9-11), p.2433 - 2436, 2011/10

 Times Cited Count:10 Percentile:62.85(Nuclear Science & Technology)

In order to obtain the engineering data on the lithium target system, which is the neutron source of the International Fusion Material Irradiation Facility (IFMIF), the design and fabrication of the IFMIF/EVEDA Lithium Test Loop are being carried out under the Engineering Validation and Engineering Design Activity (EVEDA). The loop will hold 2.5 tons of lithium. Since lithium is specified by Japanese law as a dangerous substance, countermeasures which assumed a lithium leak incident and various abnormal issues are indispensable. This paper describes about the safety principles and measures for lithium leaks of the IFMIF/EVEDA lithium test loop decided under the detailed design process.

Journal Articles

Design of purification loop and traps for the IFMIF/EVEDA Li test loop; Design of cold trap

Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Iuchi, Hiroshi; Ida, Mizuho; Yagi, Juro*; Suzuki, Akihiro*; Fukada, Satoshi*; Matsushita, Izuru*; Nakamura, Kazuyuki

Fusion Engineering and Design, 86(9-11), p.2437 - 2441, 2011/10

 Times Cited Count:19 Percentile:81.8(Nuclear Science & Technology)

Engineering Validation and Engineering Design Activities (EVEDA) for The International Fusion Materials Irradiation Facility (IFMIF) were started from July 2007 under an international agreement called ITER Broader Approach. As a major Japanese activity, EVEDA Li test loop (ELTL) to simulate hydraulic and impurity conditions of IFMIF has already designed and is under construction, in which feasibility of hydraulic stability of the liquid Li target, the purification systems of hot traps are major key issues to be validated in this loop. This paper focuses on the purification systems of the ELTL. Design of a cold trap and hot traps are discussed in this paper.

Journal Articles

Recent activities of R&D on effects of tritium water on confinement materials and tritiated water processing

Yamanishi, Toshihiko; Hayashi, Takumi; Iwai, Yasunori; Isobe, Kanetsugu; Hara, Masanori*; Sugiyama, Takahiko*; Okuno, Kenji*

Fusion Engineering and Design, 86(9-11), p.2152 - 2155, 2011/10

 Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)

It is quite significant subject how to confine the tritium in a fusion reactor. Especially, it is strongly desired to get the data for tritiated water. This is because tritiated water is much hazardous than the hydrogen form of tritium. As for the behavior of high concentration tritium water, we could get a series of valuable data for the corrosion of the tritiated water against metal materials. In the case where a metal material is in water, an oxidized layer is formed at the surface of the metal. The oxidized layer functions as a passive layer for the corrosion. However, it has been observed that the formation of the oxidized layer was prevented by the presence of tritium in water (0.23 GBq/cc). The chemical exchange column has been applied in ITER as the tritium recovery system from tritiated water. A set of data for an advanced chemical exchange column has been obtained.

Journal Articles

Design study of an AC power supply system in JT-60SA

Shimada, Katsuhiro; Baulaigue, O.*; Cara, P.*; Coletti, A.*; Coletti, R.*; Matsukawa, Makoto; Terakado, Tsunehisa; Yamauchi, Kunihito

Fusion Engineering and Design, 86(6-8), p.1427 - 1431, 2011/10

 Times Cited Count:5 Percentile:40.36(Nuclear Science & Technology)

48 (Records 1-20 displayed on this page)