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Journal Articles

Intermediate-valence icosahedral Au-Al-Yb quasicrystal

Watanuki, Tetsu; Kashimoto, Shiro*; Kawana, Daichi*; Yamazaki, Teruo*; Machida, Akihiko; Tanaka, Yukinori*; Sato, Taku*

Physical Review B, 86(9), p.094201_1 - 094201_6, 2012/09

 Times Cited Count:45 Percentile:11.69(Materials Science, Multidisciplinary)

A quasiperiodic, intermediate-valence (IV) system is realized in an icosahedral Au-Al-Yb quasicrystal. X-ray absorption spectroscopy near the Yb $$L$$$$_{3}$$-edge indicates that quasiperiodically arranged Yb ions assume a mean valence of 2.61, between a divalent state (4$$f$$$$^{14}$$, $$J$$ = 0) and a trivalent one (4$$f$$$$^{13}$$, $$J$$ = 7/2). Magnetization measurements demonstrate that the 4$$f$$ holes in this quasicrystal have a localized character. The magnetic susceptibility shows a Curie-Weiss behavior above $$sim$$100 K with an effective magnetic moment of 3.81 $$mu$$$$_{rm B}$$ per Yb. Moreover, a crystalline approximant to this quasicrystal is an IV compound. We propose a heterogeneous IV model for the quasicrystal, whereas the crystalline approximant is most likely a homogeneous IV system. At temperatures below $$sim$$10 K, specific heat and magnetization measurements reveal non-Fermi-liquid behavior in both the quasicrystal and its crystalline approximant without either doping, pressure, or field tuning.

Journal Articles

Thermal-stress analysis of IFMIF target back-wall made of reduced-activation ferritic steel and austenitic stainless steel

Ida, Mizuho; Chida, Teruo; Furuya, Kazuyuki*; Wakai, Eiichi; Nakamura, Hiroo; Sugimoto, Masayoshi

Journal of Nuclear Materials, 386-388, p.987 - 990, 2009/04

 Times Cited Count:4 Percentile:65.85(Materials Science, Multidisciplinary)

To clarify IFMIF target back-wall structures and materials with acceptable thermal-stress and deformation due to nuclear heating during the accelerator operation, thermal-stress analysis was done using a code ABAQUS and data of nuclear heating. Two types of back-wall were estimated. One is made of only 316L, and the other is made of 316L at its circumference and F82H a RAF steel at center. Effects of stress-mitigation structure with thickness 2-8 mm, and beam heat loads of 10-100% were estimated. As a result, thermal-stress in the latter back-wall is acceptable level less than 328 MPa for 316L and 455 MPa for F82H even under full heat load, if thickness of the stress-mitigation part is more than 5 mm. On the contrary, thermal-stress in the former is not acceptable. In preliminary tensile tests on dissimilar welding (316L-F82H) specimen, the fracture was occurred in base metal of 316L. Therefore, this welding is expected to be employed as the back-wall.

Journal Articles

Latest design of liquid lithium target in IFMIF

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:14 Percentile:27.98(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$$^{2}$$. 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.

JAEA Reports

Review of JAEA activities on the IFMIF liquid lithium target in FY2006

Ida, Mizuho; Nakamura, Hiroo; Chida, Teruo*; Miyashita, Makoto; Furuya, Kazuyuki*; Yoshida, Eiichi; Hirakawa, Yasushi; Miyake, Osamu; Hirabayashi, Masaru; Ara, Kuniaki; et al.

JAEA-Review 2008-008, 38 Pages, 2008/03

JAEA-Review-2008-008.pdf:9.37MB

Engineering Validation Design and Engineering Design Activity (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF) is under going. IFMIF is an accelerator-based Deuterium-Lithium (D-Li) neutron source to produce intense high energy neutrons and a sufficient irradiation volume for testing candidate materials for fusion reactors. To realize such a condition, 40 MeV deuteron beam with a current of 250 mA is injected into high speed liquid Li flow with a speed of 20 m/s. In target system, nuclear heating due to neutron causes thermal stress especially on a back-wall of the target assembly. In addition, radioactive species such as beryllium-7, tritium and activated corrosion products are generated. In this report, thermal stress analyses of the back-wall, mechanical tests on weld specimen made of the back-wall material, estimations of beryllium-7 behavior and worker dose at the IFMIF Li loop and consideration on major EVEDA tasks are summarized.

Journal Articles

Design of a lip seal-replaceable backwall for IFMIF liquid lithium target

Nakamura, Hiroo; Ida, Mizuho; Chida, Teruo; Furuya, Kazuyuki*; Sugimoto, Masayoshi

Fusion Engineering and Design, 82(15-24), p.2671 - 2676, 2007/10

 Times Cited Count:5 Percentile:59.58(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Thermo-structural analysis of backwall in IFMIF lithium target, 2

Chida, Teruo; Ida, Mizuho; Nakamura, Hiroo; Sato, Toru*; Sugimoto, Masayoshi

JAEA-Technology 2007-048, 40 Pages, 2007/08

JAEA-Technology-2007-048.pdf:5.42MB

This report describes results of thermo-structural analysis of a backwall in international fusion material irradiation facilities (IFMIF) lithium target preformed during FY2007. The IFMIF is an accelerator-based intense neutron source for testing candidate materials for fusion reactors. Since the backwall is operating under a severe neutron irradiation of 50 dpa/year and a maximum nuclear heating rate of 25 W/cm$$^{3}$$, thermo-structural design is one of critical issues in a target design. Since previous model included only the backwall, a model including a part of target assembly is applied. In this analysis, three models were calculated. First model is a basic geometry adding a part of the target assembly to the backwall. Second model is a modified geometry which has a thin backwall. In a third model, a lip seal with a stress mitigation structure was applied to the second model. Calculation results showed that, in the third model, a thermal stress at a center of the backwall was 146 MPa below a permissible stress of F82H (455MPa: an yield strength at 300$$^{circ}$$C) and maximum stress was 286 MPa below a permissible stress of SUS316L (328MPa: 3Sm value at 300$$^{circ}$$C). These results showed a prospect of the present backwall configuration.

Journal Articles

Thermo-structural analysis and design consideration of the replaceable backwall in IFMIF liquid lithium target

Nakamura, Hiroo; Ida, Mizuho; Chida, Teruo; Shiba, Kiyoyuki; Shimizu, Katsusuke*; Sugimoto, Masayoshi

Journal of Nuclear Materials, 367-370(2), p.1543 - 1548, 2007/08

 Times Cited Count:2 Percentile:79.6(Materials Science, Multidisciplinary)

The IFMIF is an accelerator-based intense neutron source for testing candidate materials of fusion reactor. Intense neutrons are emitted inside the Li flow through a backwall. The backwall made of 316L stainless steel or RAFM is attached to the target assembly with a lip seal welded by YAG laser. Since the backwall is operating under a severe neutron irradiation of 50 dpa/year and a maximum nuclear heating rate of 25 W/cm$$^{3}$$, thermo-structural design is one of critical issues in a target design. Thermal stress was calculated by ABAQUS code. As a permissible stress, yield strength at 300$$^{circ}$$C was used. In a case of the 316 stainless steel backwall, a maximum thermal stress was more than the permissible stress(164MPa). On the other hand, in case of the F82H backwall, a maximum thermal stress is was below the permissible stress(455MPa). Therefore, F82H is recommended as a backwall material.

Journal Articles

Upgrade program of ECRH system for GAMMA10

Imai, Tsuyoshi*; Tatematsu, Yoshinori*; Numakura, Tomoharu*; Sakamoto, Keishi; Minami, Ryutaro*; Watanabe, Osamu*; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Kamata, Yasuhiro*; Machida, Norihito*; et al.

Fusion Science and Technology, 51(2T), p.208 - 212, 2007/02

 Times Cited Count:9 Percentile:40.9(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Characteristics of 28 GHz gyrotron for ECRH on GAMMA10

Kamata, Yasuhiro*; Imai, Tsuyoshi*; Tatematsu, Yoshinori*; Watanabe, Osamu*; Minami, Ryutaro*; Saito, Teruo*; Sakamoto, Keishi; Kariya, Tsuyoshi*; Mitsunaka, Yoshika*; Machida, Norihito*; et al.

Fusion Science and Technology, 51(2T), p.412 - 414, 2007/02

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Review of JAEA activities on the IFMIF liquid lithium target in FY2005

Ida, Mizuho; Nakamura, Hiroo; Chida, Teruo; Sugimoto, Masayoshi

JAEA-Review 2006-009, 28 Pages, 2006/03

JAEA-Review-2006-009.pdf:3.95MB

The International Fusion Materials Irradiation Facility (IFMIF) is being jointly planned to provide an accelerator-based Deuterium-Lithium (D-Li) neutron source to produce intense high energy neutrons (2 MW/m$$^{2}$$) up to 200 dpa and a sufficient irradiation volume (500 cm$$^{3}$$) for testing candidate materials and components up to about a full lifetime of their anticipated use in ITER and DEMO. To realize such a condition, 40 MeV deuteron beam with a current of 250 mA is injected into high speed liquid Li flow with a speed of 20 m/s. In target system, radioactive species such as $$^{7}$$Be, tritium and activated corrosion products are generated. In addition, back wall operates under severe conditions of neutron irradiation damage (about 50 dpa/y). In this paper, the thermal structural analysis and the accessibility evaluation of the IFMIF Li loop are summarized as JAEA activities on the IFMIF target system performed in FY2005.

Journal Articles

Thermal diffusivity of high burnup UO$$_{2}$$ pellet

Nakamura, Jinichi; Uchida, Masaaki; Uetsuka, Hiroshi; Furuta, Teruo

IAEA-TECDOC-1036, 0, p.127 - 138, 1998/08

no abstracts in English

Journal Articles

Experimental plan on irradiated LWR fuels at JAERI

Uetsuka, Hiroshi; Nakamura, Jinichi; Nagase, Fumihisa; Uchida, Masaaki; Furuta, Teruo

Fuel Performance Experiment and Analysis and Computerised Man-Machine Communication, p.1 - 11, 1990/09

no abstracts in English

Oral presentation

Thermal structure analysis and dose estimation for lithium target of the international fusion materials irradiation facility IFMIF

Ida, Mizuho; Nakamura, Hiroo; Chida, Teruo; Ara, Kuniaki; Sugimoto, Masayoshi

no journal, , 

no abstracts in English

Oral presentation

IFMIF thermostructural analysis in the target back wall

Chida, Teruo; Ida, Mizuho; Nakamura, Hiroo; Sugimoto, Masayoshi; Simakov, S. P.*

no journal, , 

no abstracts in English

Oral presentation

Emulsification technology of Aomori Hiba oil and its' antibacterial effect against staphylococci

Okabe, Toshihiro*; Ono, Hiroyuki*; Hatayama, Ichiro*; Waguri, Atsushi*; Sawada, Yuzuru*; Tsugawa, Hidehito*; Ichida, Tadao*; Nakane, Akio*; Sano, Teruo*; Tanaka, Kazuaki*; et al.

no journal, , 

Oral presentation

Intermediate-valence Yb-based quasicrystals

Watanuki, Tetsu; Kawana, Daichi*; Machida, Akihiko; Tsai, A. P.*; Kashimoto, Shiro*; Tanaka, Yukinori*; Ishimasa, Tsutomu*; Yamazaki, Teruo*; Sato, Taku*

no journal, , 

Quasiperiodic intermediate-valence systems were prepared by applying pressure to Yb-based quasicrystals. In these systems, each quasiperiodic lattice point has a charge degree of freedom. Synchrotron radiation X-ray absorption spectroscopy experiments near the Yb L3-edge demonstrate that the Yb valence in a Cd-Yb icosahedral quasicrystal increases continuously upon compression from a divalent state at ambient pressure and reaches 2.33 at 31.7 GPa, where the quasiperiodically arranged Yb ions take a valence fluctuation state. For the case of a Cd-Mg-Yb icosahedral quasicrystal, the Yb valence reaches a value of 2.71 at 57.6 GPa. By following the trend of Yb-based intermediate-valence crystalline compounds, this large valence increase suggests that the 4f electron system in this quasicrystal varies from a valence fluctuation regime to a strong correlated electron regime. Additionally, we have recently found that Au-Al-Yb icosahedral quasicrystal is an IV compound at ambient pressure.

Oral presentation

Intermediate-valence Yb-based quasicrystals, measurements of the valence and physical properties

Watanuki, Tetsu; Kawana, Daichi*; Machida, Akihiko; Kashimoto, Shiro*; Tanaka, Yukinori*; Ishimasa, Tsutomu*; Yamazaki, Teruo*; Sato, Taku*; Tsai, A. P.*

no journal, , 

no abstracts in English

Oral presentation

Intermediate-valence icosahedral Au-Al-Yb quasicrystal

Watanuki, Tetsu; Kashimoto, Shiro*; Yamazaki, Teruo*; Kawana, Daichi*; Machida, Akihiko; Tanaka, Yukinori*; Ishimasa, Tsutomu*; Sato, Taku*

no journal, , 

A quasiperiodic, intermediate-valence (IV) system is realized in an icosahedral Au-Al-Yb quasicrystal. X-ray absorption spectroscopy near the Yb L3-edge indicates that quasiperiodically arranged Yb ions assume a mean valence of 2.61, between a divalent state (4f14, J = 0) and a trivalent one (4f13, J = 7/2). Magnetization measurements demonstrate that the 4f holes in this quasicrystal have a localized character. The magnetic susceptibility shows a Curie-Weiss behavior above 100 K with an effective magnetic moment of 3.81 muB per Yb. Moreover, a crystalline approximant to this quasicrystal is an IV compound. We propose a heterogeneous IV model for the quasicrystal, whereas the crystalline approximant is most likely a homogeneous IV system. At temperatures below 10 K, specific heat and magnetization measurements reveal non-Fermi-liquid behavior in both the quasicrystal and its crystalline approximant without either doping, pressure, or field tuning.

18 (Records 1-18 displayed on this page)
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