Mechanical properties of full austenitic welding joint at cryogenic temperature for the ITER toroidal field coil structure

Iguchi, Masahide; Saito, Toru; Kawano, Katsumi; Chida, Yutaka; Nakajima, Hideo; Ogawa, Tsuyoshi*; Katayama, Yoshinori*; Ogata, Hiroshige*; Minemura, Toshiyuki*; Tokai, Daisuke*; et al.

Fusion Engineering and Design, 88(9-10), p.2520 - 2524, 2013/10

https://doi.org/10.1016/j.fusengdes.2013.02.165

ITER TFC structures are large welding structures made of heavy thick stainless steels. JAEA plans to apply narrow gap TIG welding with FMYJJ1 which is full austenitic stainless filler material to manufacture TFC structure. FMYJJ1 is specified in "Codes for Fusion Facilities -Rules on Superconducting Magnet Structure (2008)". In order to evaluate effect of base material combinations and thickness of welded joint on tensile properties at 4 K, tensile tests were conducted at 4 K by using tensile specimens taken from 40 mm thickness weld joints of four combinations and 200 mm thickness ones of two combinations of base materials. These weld joints were manufactured by one side narrow gap TIG welding with FMYJJ1. As the results, it was confirmed that yield and tensile strengths of welded joint at 4K were decreased with decreasing of nitrogen of base material, and there were no large distribution of strengths at 4 K along the thickness of welded joints of 200 mm thickness.

Development in fabrication structures for the ITER toroidal field coils

Iguchi, Masahide; Chida, Yutaka; Nakajima, Hideo; Ogawa, Tsuyoshi*; Katayama, Yoshinori*; Ogata, Hiroshige*; Minemura, Toshiyuki*; Miyabe, Keisuke*; Tokai, Daisuke*; Niimi, Kenichiro*

Teion Kogaku, 47(3), p.193 - 199, 2012/03

https://doi.org/10.2221/jcsj.47.193

Japan Atomic Energy Agency (JAEA) has conducted qualification and rationalization activities in Japan in order to rationalize manufacturing procedure of ITER Toroidal Field (TF) coil structures. The activities included qualification of structural materials and qualification of welding procedure according to Japan Society of Mechanical Engineers (JSME) code constituted for fusion devices, demonstration of the manufacturing method and procedures through full-scale segments of TF coil structure. From results of these activities, JAEA confirmed applicability of JSME code to actual series TF coil structures as quality control method hence the quality of structural materials and weld joints of Gas Tungsten Arc Welding (GTAW) were satisfied ITER requirement. In addition, JAEA obtained knowledge of welding deformation of actual TF coil structures. This paper describes results of these qualification and development activities for TF coil structure.

Excavation analysis of vertical shaft in sedimentary rock taken into account strain softening and depth variation of rock properties

Sanada, Hiroyuki; Matsui, Hiroya; Ogawa, Toyokazu*; Kinomura, Koji*; Aoki, Tomoyuki*; Yamamoto, Takuya*

JAEA-Research 2009-050, 57 Pages, 2010/01

JAEA-Research-2009-050.pdf:8.14MB

It is important to understand EDZ in assessing performance of repository and designing of plug. It is known that it remains possible that the large-scale EDZ is generated due to strain localization from boring investigations and tunnel excavation analyses and rock properties changes with increase of depth. Excavation analysis of vertical shaft in sedimentary rock taken into account strain softening, depth variation of rock properties and the actual construction procedure had been done in order to understand EDZ of Horonobe URL. The large-scale EDZ due to strain localization was generated around the border between Koetoi formation and Wakkanai formation. From result obtained from excavation analysis, scale of EDZ obtained from excavation analysis is from 60 cm to 120 cm. And it was estimated that seismic velocity changed by 20 percent, elastic modulus changed by 30 percent and hydraulic conductivity changed by 0.1 m/s order.

Observation of high- quasiparticle states in Cm by in-beam -ray spectroscopy using heavy-ion transfer reactions

Ishii, Tetsuro; Makii, Hiroyuki*; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shigematsu, Soichiro*; Kaneko, Junichi*; Shizuma, Toshiyuki; et al.

Physical Review C, 78(5), p.054309_1 - 054309_11, 2008/11

https://doi.org/10.1103/PhysRevC.78.054309

Durability of triple-junction solar cell for HIHT environments, venus and mercury exploration missions

Imaizumi, Mitsuru*; Toyota, Hiroyuki*; Shimada, Toru*; Ogawa, Hiroyuki*; Tajima, Michio*; Hisamatsu, Tadashi*; Nakamura, Kazuyo*; Takamoto, Tatsuya*; Sato, Shinichiro; Oshima, Takeshi

Proceedings of 8th European Space Power Conference (CD-ROM), 6 Pages, 2008/09

Results of our study of effects of high-light-intensity and high-temperature conditions (HIHT) on the output performance of an InGaP/GaAs/Ge triple-junction solar cell are described herein. The HIHT conditions are adjusted for spacecraft environments expected for a Venus mission (Planet-C) and a Mercury mission (MMO) to be undertaken by the Japan Aerospace Exploration Agency (JAXA). Measurements of currentvoltage characteristics under high light intensity for a wide range of cell temperatures exhibit a kinked pattern at 0 current at +200C. The thermal cycle test results for bare cells with a wide temperature range show no output performance degradation. Continuous operation tests of 3J cells under HIHT conditions reveal gradual current output degradation, implying that solar panel design should address decreased output specifically.

Evaluation on stability of shaft during excavation, considerating strain softening behavior surrounding rock mass

Kinomura, Koji*; Ogawa, Toyokazu*; Aoki, Tomoyuki*; Yamamoto, Takuya*; Matsui, Hiroya; Sanada, Hiroyuki

Dai-37-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.307 - 312, 2008/01

no abstracts in English

Z dependence of the deformed shell gap; In-beam -ray spectroscopy of neutron-rich Pu

Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato*; Ichikawa, Shinichi; et al.

Physical Review C, 76(6), p.061301_1 - 061301_5, 2007/12

https://doi.org/10.1103/PhysRevC.76.061301

We have measured deexcitation rays for the first time in the neutron-rich nuclei of Pu and Pu produced by the (O, O) and the (O, O) reactions, respectively. The ground-state band of Pu was established up to 12 states. The systematics of the moments of inertia of Pu isotopes suggests that the deformed subshell closure disappears in these isotopes. The measurements of deexcitation rays in Pu shows a small energy spacing between neutron orbitals at , which explans the disappearance of the subshell closure.

Ground-state bands of neutron-rich Th and U nuclei and implication of spherical shell closure at

Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; et al.

Physical Review C, 76(1), p.011303_1 - 011303_5, 2007/07

https://doi.org/10.1103/PhysRevC.76.011303

The ground-state bands of the neutron-rich Th and U nuclei were established up to spin 10 and 8, respectively, by in-beam -ray spectroscopy using the (O, Ne) two-proton pickup reaction with a U and a Pu target. Deexcitation rays in Th and U were identified by selecting the kinetic energies of Ne using Si - detectors. The excitation energies of the first 2 states in U and Pu isotopes have local minima at , suggesting the possibility that nuclei with have a spherical shell closure of . Calculation using the Koura-Yamada single-particle potential gives an energy gap of 1.8 MeV at for U.

Stability analysis of underground opening during excavation, taking time-dependent behaviour of surrounding rock mass into consideration

Ogawa, Toyokazu*; Aoki, Tomoyuki*; Jo, Mayumi*; Matsui, Hiroya; Horii, Hideyuki*

Dai-36-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu, p.39 - 44, 2007/01

In case rock exhibits time-dependent deformation, it is important to evaluate this effect on the tunnel stability, since the rock deforms elastically as well as inelatically even at the time of excavation. This paper introduces an engineering approach method to explain the effect of time-dependent deformation of rock at tunnel excavation stages on the stability. The mechanical parameters to describe a Burgers type rheological model are determined, based upon the drained triaxial creep test results performed on mudstone samples. With the parameters determined, plane-strain 2 dimensional numerical analyses are subsequently performed. In the analysis a couple of indices to describe the degree and timing of time-dependent deformation are introduced with reference to the instantaneous elastic deformation, and their effects on the amount of deformation and support pressure subsequent to the support erection are investigated.

Measurement of Seismic Wave Velocities on Soft-Sedimentary Rocks from Horonobe Under Confining Pressure

Ogawa, Toyokazu*; Matsui, Hiroya

JNC TN8400 2005-011, 157 Pages, 2005/02

JNC-TN8400-2005-011.pdf:181.57MB

Horonobe Underground Research Center has been conducting researches and developments into geological disposal of high-level radioactive wastes in sedimentary rocks. In the 2003 borehole investigation programmes, 3 boreholes (HDB-6, 7, and 8) were drilled in order to acquire geoscientific information. This technical report presents the results of elastic wave velocity measurements under confining pressure, carried out on the rock cores extracted from BH HDB-6. The main observations which became clear from the laboratory tests are as follows: 1. the basic physical properties of the rock specimens are consistent with the existing measured values. Moreover, when the wet sample is dried, although P wave velocity at first shows a downward tendency, it increases gradually and approaches the dry velocity as the degree of saturation decreases. Therefore, it is felt that the sample is uniformly dried across the cross-sectional area. ; 2. It appears that the elastic wave velocities of the Horonobe sedimentary rocks are dependent upon pressure. However shear rigidity remains unchanged, even if the saturation conditions of pores change (from wet to dry conditions). In the study of anisotropy of velocities, horizontal velocity seems larger than the vertical one. Although there was no remarkable influence on elastic wave velocities when the loading and unloading of confining pressure were repeated, a certain amount of hysteresis could be observed in porosity. Continuous investigation is required. ; 3. Measured wet velocity may practically be used in evaluating in-situ velocity measurement results.