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Journal Articles

Radiation-induced thermoelectric sensitivity in the mineral-insulated cable of magnetic diagnostic coils for ITER

Nishitani, Takeo; Vayakis, G.*; Yamauchi, Michinori*; Sugie, Tatsuo; Kondoh, Takashi; Shikama, Tatsuo*; Ishitsuka, Etsuo; Kawashima, Hisato

Journal of Nuclear Materials, 329-333(Part2), p.1461 - 1465, 2004/08

 Times Cited Count:16 Percentile:70.43(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Measurement of deuterium and tritium retentions on the surface of JT-60 divertor tiles by means of nuclear reaction analysis

Ochiai, Kentaro; Hayashi, Takao; Kutsukake, Chuzo; Goto, Yoshitaka*; Masaki, Kei; Arai, Takashi; Miya, Naoyuki; Nishitani, Takeo

Journal of Nuclear Materials, 329-333(Part1), p.836 - 839, 2004/08

 Times Cited Count:4 Percentile:29.52(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Radioactivity of the vanadium-alloy induced by D-T neutron irradiation

Sato, Satoshi; Tanaka, Teruya*; Hori, Junichi; Ochiai, Kentaro; Nishitani, Takeo; Muroga, Takeo*

Journal of Nuclear Materials, 329-333(Part2), p.1648 - 1652, 2004/08

 Times Cited Count:2 Percentile:17.24(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Elastic-plastic FEM analysis on low cycle fatigue behavior for alumina dispersion-strengthened copper/stainless steel joint

Nishi, Hiroshi

Journal of Nuclear Materials, 329-333(Part2), p.1567 - 1570, 2004/08

 Times Cited Count:9 Percentile:52.9(Materials Science, Multidisciplinary)

Elastic-plastic finite element analysis was performed for low cycle fatigue behavior of stainless steel/alumina-dispersion-strengthened copper (DS Cu) joint in order to investigate the fatigue life and the fracture behavior of the joint. As the results, a strain concentration was occurred near the interface of DS Cu for small strain range, however, in the DS Cu for large strain range. The fatigue life and fracture point were evaluated taking account for the strain concentration. The fatigue life and fracture point were consistent with those of the low cycle fatigue test.

Journal Articles

In-situ tritium recovery behavior from Li$$_{2}$$TiO$$_{3}$$ pebble bed under neutron pulse operation

Tsuchiya, Kunihiko; Kikukawa, Akihiro*; Hoshino, Tsuyoshi; Nakamichi, Masaru; Yamada, Hirokazu*; Yamaki, Daiju; Enoeda, Mikio; Ishitsuka, Etsuo; Kawamura, Hiroshi; Ito, Haruhiko; et al.

Journal of Nuclear Materials, 329-333(Part2), p.1248 - 1251, 2004/08

 Times Cited Count:10 Percentile:56.08(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Low activation materials applicable to the IFMIF accelerator

Sugimoto, Masayoshi; Takeuchi, Hiroshi

Journal of Nuclear Materials, 329-333(Part1), p.198 - 201, 2004/08

 Times Cited Count:4 Percentile:29.52(Materials Science, Multidisciplinary)

IFMIF is an accelerator-based intense neutron source for developing fusion reactor materials, and a stable and continuous operation is a primary importance. The radioactivity produced by the beam loss prolongs the cooling time before maintenance and results in a potential limit to the availability. The materials selection is important for minimizing the total radioactivity produced by ion beam and neutrons, after about one day cooling time in advance of hands-on maintenance. For the major parts, Cu for cavity and Al for beam duct, the beam loss needs to be reduced below 5nA/m. Such a low loss can be realized by suppressing the beam halo and by using the scrapers made from high-Z material, Ta, to cut the tail of beam. The insertion points of the scrapers are determined from the beam size evolution along the accelerator and the available room for radiation shielding around them. The reduction of the radioactivity after the whole lifetime of facility is another issue and the possibility to use low activation materials coating for cavity and beam duct is presented.

Journal Articles

Non-destructive analysis of impurities in beryllium, affecting evaluation of the tritium breeding ratio

Verzilov, Y. M.; Ochiai, Kentaro; Klix, A.; Sato, Satoshi; Wada, Masayuki*; Yamauchi, Michinori*; Nishitani, Takeo

Journal of Nuclear Materials, 329-333(Part2), p.1337 - 1341, 2004/08

 Times Cited Count:4 Percentile:29.52(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Experimental evaluation of tritium permeation through stainless steel tubes of heat exchanger from primary to secondary water in ITER

Nakamura, Hirofumi; Nishi, Masataka

Journal of Nuclear Materials, 329-333(Part1), p.183 - 187, 2004/08

 Times Cited Count:24 Percentile:81.31(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Present status of the liquid lithium target facility in the international fusion materials irradiation facility (IFMIF)

Nakamura, Hiroo; Riccardi, B.*; Loginov, N.*; Ara, Kuniaki*; Burgazzi, L.*; Cevolani, S.*; Dell'Ocro, G.*; Fazio, C.*; Giusti, D.*; Horiike, Hiroshi*; et al.

Journal of Nuclear Materials, 329-333(1), p.202 - 207, 2004/08

 Times Cited Count:14 Percentile:66.35(Materials Science, Multidisciplinary)

International Fusion Materials Irradiation Facility (IFMIF), being developed by EU, JA, RF and US, is a deuteron-lithium (Li) reaction neutron source for fusion materials testing. In the end of 2002, 3 year Key Element technology Phase (KEP) to reduce the key technology risk factors has been completed. This paper describes these KEP tasks results. To evaluate Li flow characteristics, a water and Li flow experiments have been done. To develop Li purification system, evaluation of nitrogen and tritium gettering materials have been done. Conceptual design of remote handling and basic experiment have been donde. In addition, safety analysis and diganostics design have been done. In the presentation, the latest design and future prospects will be also summarized.

Journal Articles

Energetic deuterium and helium irradiation effects on chemical structure of CVD diamond

Sasaki, Masayoshi*; Morimoto, Yasutomi*; Kimura, Hiromi*; Takahashi, Koji; Sakamoto, Keishi; Imai, Tsuyoshi; Okuno, Kenji*

Journal of Nuclear Materials, 329-333(Part1), p.899 - 903, 2004/08

A CVD diamond has been the reference material of a torus widow for a rf heating system in a fusion reactor. Since the window is in the circumstance of tritium, helium and radio activated dust, it is important to elucidate the effect of ions on chemical structure of the diamond, existing states of tritium and tritium inventory. Polycrystalline CVD diamond disks($$phi$$=10.0mm, t=0.21mm) used in this study are the same grade as rf windows. After sputtering the surface with 1.0 keV Ar$$^{+}$$ to remove oxygen impurity, the sample was irradiated with deuterium (D$$_{2}$$$$^{+}$$) or helium ions (He$$^{+}$$) at an angle of 0 degrees to the surface normal. The irradiation energies of deuterium and helium are 0.25 keV D$$^{+}$$ and 0.45 keV He$$^{+}$$, respectively. The structural change of the irradiated sample was measured by X-ray Photoelectron Spectroscopy (XPS) technique. The C1s peak shift toward lower binding energy side was observed when deuterium ions irradiated. This result indicates that the diamond changes to amorphous carbon due to formation of C-D bond.

Journal Articles

The Present status and future prospects of the ITER project

Shimomura, Yasuo

Journal of Nuclear Materials, 329-333(1), p.5 - 11, 2004/08

 Times Cited Count:22 Percentile:79.37(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Synergistic effect of displacement damage and helium atoms on radiation hardening of F82H at TIARA facility

Ando, Masami; Wakai, Eiichi; Sawai, Tomotsugu; Tanigawa, Hiroyasu; Furuya, Kazuyuki; Jitsukawa, Shiro; Takeuchi, Hiroshi; Oka, Keiichiro*; Onuki, Somei*; Koyama, Akira*

Journal of Nuclear Materials, 329-333(2), p.1137 - 1141, 2004/08

 Times Cited Count:48 Percentile:94(Materials Science, Multidisciplinary)

One of the most crucial issues on R&D of reduced activation ferritic/martensitic steels is the effect of helium on the degradation of fracture toughness. The synergistic effects of displacement damage and helium on F82H steel can be partially simulated by martensitic steels doped with $$^{10}$$B or $$^{58}$$Ni in a mixed spectrum fission reactor. However, the control of helium production rate is difficult and the chemical effects of B or Ni doping on mechanical property are not small. Therefore, multi-ion irradiation method is the most convenient and accurate method to simulate various irradiation conditions. Moreover, the effects of helium on irradiation hardening behavior can be examined by combining ion-irradiation with ultra micro-indentation technique. The purpose of this study is to examine the extra component of radiation hardening due to implanted helium in F82H. The extra component of irradiation hardening due to helium was hardly detected in the dual-beam irradiation. Therefore, the effect on irradiation hardening below 630K of helium ($$<$$500 appm) was very small.

Journal Articles

Irradiation test on Mo- and W-mirrors for ITER by low energy deuterium ions

Sugie, Tatsuo; Kasai, Satoshi; Taniguchi, Masaki; Nagatsu, Masaaki*; Nishitani, Takeo

Journal of Nuclear Materials, 329-333(2), p.1481 - 1485, 2004/08

 Times Cited Count:30 Percentile:86.18(Materials Science, Multidisciplinary)

In ITER, the effect of lower energy particle bombardment is important for mirrors located near the divertor where the low temperature plasma is formed. The test pieces of molybdenum mirrors and a tungsten mirror were irradiated by high flux and low energy (67-80 eV) deuterium ions using SLEIS (Super Low Energy Ion Source with High Ion Flux) facility at the temperature of around 100 $$^{circ}$$C. The molybdenum mirror manufactured by sintering and melting the thin layer of the surface by electron beam in order to eliminate holes on the surface has a higher reflectivity before irradiation than the mirrors without melting the surface, but the reflectivity decreases rapidly with the irradiation fluence due to the generation of blisters on the mirror surface. The reflectivity of molybdenum mirror manufactured by sintering only did not decrease so significantly (less than 10 % at the fluence of 1.3 $$times$$ 10$$^{25}$$ m$$^{-2}$$). The molybdenum and tungsten mirrors manufactured by sintering without melting the surface have a potential for plasma facing mirrors in ITER.

Journal Articles

Thermal diffusivity/conductivity of Tyranno SA fiber- and Hi-Nicalon type S fiber-reinforced 3-D SiC/SiC composites

Yamada, Reiji; Igawa, Naoki; Taguchi, Tomitsugu

Journal of Nuclear Materials, 329-333(Part1), p.497 - 501, 2004/08

 Times Cited Count:28 Percentile:84.72(Materials Science, Multidisciplinary)

SiC fiber reinforced SiC composites (SiC/SiC) have a potential for a structural material for a blanket wall of advanced fusion reactors. To reduce thermal stresses in the wall under heavy thermal loads SiC/SiC composites are expected to have high thermal conductivity as possible. Advanced SiC fibers recently developed, such as Tyranno SA and Hi-Nicalon Type S have been employed for weaving 3D textures as well as those 2D unwoven fabrics. The CVI and PIP/CVI fabrication methods were used. The thermal conductivity at RT was 40-50 W/mK and 35-40 W/mK for Tyranno CVI and PIP/CVI composites, respectively, whereas about 25 and about 17 W/mK at 1000 $$^{circ}$$C. 2D unwoven CVI composites had less than 12 W/mK for RT-1000 $$^{circ}$$C. For Hi-Nicalon Type S, 3D CVI composites had about 35 and about 20 for RT and 1000 $$^{circ}$$C, respectively. The reason of these high thermal conductivities was ascribed to higher density as well as better SiC crystallinity. The fiber configuration effects on the thermal conductivity of SiC/SiC composites were dominant in the low temperature region.

Journal Articles

Effects of heat treatment process for blanket fabrication on mechanical properties of F82H

Hirose, Takanori; Shiba, Kiyoyuki; Sawai, Tomotsugu; Jitsukawa, Shiro; Akiba, Masato

Journal of Nuclear Materials, 329-333(Part1), p.324 - 327, 2004/08

 Times Cited Count:55 Percentile:95(Materials Science, Multidisciplinary)

Reduced activation ferritic/martensitic steel, RAFs is the leading candidates for the structural materials of breeding blankets. HIP is examined as a near-net-shape fabrication process for this structure. The HIP requires heating above the normalizing temperature and the final microstructural features depends on the HIP processing conditions. Conventional HIP process caused a prior-austenite grain (PAG) coarsening of RAFs and subsequent increase of ductile brittle transition temperature. Japanese RAFs F82H and its modified steels were investigated by metallurgical method after isochronal heat treatment up to 1473K simulating HIP equivalent thermal hysteresis. Although Conventional F82H IEA heat showed significant grain growth after conventional solid HIP conditions (1313K $$times$$ 2hr.), F82H with 0.1wt.% tantalum kept fine grain after the same heat treatment. On the other hands, conventional RAF/Ms with coarse grain were recovered by the post HIP normalizing at temperature below TaC dissolution temperature. This process can refine the PAG size of F82H more than ASTM grain size number 7.

Journal Articles

FT-IR study on interaction of irradiated deuteron with defects in Li$$_{2}$$O

Tanigawa, Hisashi; Tanaka, Satoru*; Enoeda, Mikio; Akiba, Masato

Journal of Nuclear Materials, 329-333(2), p.1291 - 1294, 2004/08

 Times Cited Count:4 Percentile:29.52(Materials Science, Multidisciplinary)

In order to elucidate the interaction of hydrogen isotopes with irradiation defects, infrared absorption spectroscopy was conducted for a single crystal of Li$$_{2}$$O. Using FT-IR, O-D stretching vibration from the bulk Li$$_{2}$$O was observed under deutron irradiation. Under and after the irradiation, several peaks were observed in the O-D stretching vibration region and these peaks had different dependence on conditions of the irradiation. From the observed behaviour of the peaks, it was suggested that most of the irradiated deutron existed in Li$$_{2}$$O without O-D bonding because of interaction with the defects.

Journal Articles

Present status of beryllide R&D as neutron multiplier

Kawamura, Hiroshi; Takahashi, Heishichiro*; Yoshida, Naoaki*; Mishima, Yoshinao*; Ishida, Kiyohito*; Iwadachi, Takaharu*; Cardella, A.*; Van der Laan, J. G.*; Uchida, Munenori*; Munakata, Kenzo*; et al.

Journal of Nuclear Materials, 329-333(1), p.112 - 118, 2004/08

 Times Cited Count:32 Percentile:87.39(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Bend-fatigue properties of 590 MeV proton irradiated JPCA and 316F SS

Saito, Shigeru; Kikuchi, Kenji; Usami, Koji; Ishikawa, Akiyoshi; Nishino, Yasuharu; Kawai, Masayoshi*; Dai, Y.*

Journal of Nuclear Materials, 329-333(Part1), p.1093 - 1097, 2004/08

 Times Cited Count:6 Percentile:41.03(Materials Science, Multidisciplinary)

In several institutes, research and development for an accelerator-driven spallation neutron source have been progressed. A beam window of a target will be subjected to proton/neutron irradiation, pressure wave and thermal stresses accompanied by high-energy proton beam injection. To obtain the irradiation data, the SINQ target irradiation program (STIP) at Paul Scherrer Institute (PSI) has been progressing. JAERI takes part in STIP and shares the PIE work. The STIP specimens are very small so that we developed a new fatigue-testing machine with ceramic piezoelectric actuator. The results showed that the numbers of cycles to failure (Nf) on the irradiated specimens were less than that of unirradiated specimens. Dpa dependence of Nf was not clearly seen in the irradiation conditions. On the other hand, fracture surface varied with irradiation conditions. Specimens irradiated at low temperature fractured in ductile manner. However, interglanular fractured surface was observed for 316F SS irradiated up to 12.5 dpa at 360$$^{circ}$$C.

Journal Articles

Microstructure property analysis of HFIR-irradiated reduced-activation ferritic/martensitic steels

Tanigawa, Hiroyasu; Hashimoto, Naoyuki*; Sakasegawa, Hideo*; Klueh, R. L.*; Sokolov, M. A.*; Shiba, Kiyoyuki; Jitsukawa, Shiro; Koyama, Akira*

Journal of Nuclear Materials, 329-333(1), p.283 - 288, 2004/08

 Times Cited Count:18 Percentile:75.49(Materials Science, Multidisciplinary)

Reduced-activation ferritic/martensitic steels (RAFs) were developed as candidate structural materials for fusion power plants. In a previous study, it was reported that ORNL9Cr-2WVTa and JLF-1 (Fe-9Cr-2W-V-Ta-N) steels showed smaller ductile-brittle transition temperature (DBTT) shifts compared to IEA modified F82H (Fe-8Cr-2W-V-Ta) after neutron irradiation up to 5 dpa at 573K. This difference in DBTT shift could not be interpreted as an effect of irradiation hardening, and it is also hard to be convinced that this difference was simply due to a Cr concentration difference. To clarify the mechanisms of the difference in Charpy impact property between these steels, various microstructure analyses were performed.

Journal Articles

Mechanical characterization of austenitic stainless steel ion irradiated under external stress

Ioka, Ikuo; Futakawa, Masatoshi; Naito, Akira; Nanjo, Yoshiyasu*; Kiuchi, Kiyoshi; Naoe, Takashi*

Journal of Nuclear Materials, 329-333(Part2), p.1142 - 1146, 2004/08

 Times Cited Count:0 Percentile:0.01(Materials Science, Multidisciplinary)

no abstracts in English

46 (Records 1-20 displayed on this page)