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Aburadani, Atsushi; Takeda, Nobukazu; Shigematsu, Soichiro; Murakami, Shin; Tanigawa, Hisashi; Kakudate, Satoshi; Nakahira, Masataka*; Hamilton, D.*; Tesini, A.*
Fusion Engineering and Design, 88(9-10), p.1978 - 1981, 2013/10
Times Cited Count:2 Percentile:18.46(Nuclear Science & Technology)no abstracts in English
Takeda, Nobukazu; Aburadani, Atsushi; Tanigawa, Hisashi; Shigematsu, Soichiro; Kozaka, Hiroshi; Murakami, Shin; Kakudate, Satoshi; Nakahira, Masataka; Tesini, A.*
Fusion Engineering and Design, 88(9-10), p.2186 - 2189, 2013/10
Times Cited Count:2 Percentile:18.46(Nuclear Science & Technology)R&D for rail deployment equipment was performed for the ITER blanket remote handling system. The target torque for the automatic operation was investigated. The result shows that the 20% of the rated torque is adequate as the torque limitation for the automatic operation. A schedule for the procurement of the blanket remote handling system, which will be delivered to the ITER in 2020, was also shown.
Tanigawa, Hisashi; Aburadani, Atsushi; Shigematsu, Soichiro; Takeda, Nobukazu; Kakudate, Satoshi; Mori, Seiji*; Jokinen, T.*; Merola, M.*
Fusion Engineering and Design, 87(7-8), p.999 - 1003, 2012/08
Times Cited Count:13 Percentile:68.80(Nuclear Science & Technology)This paper presents results of R&D activities where the laser and TIG welding tools were developed to apply the blanket hydraulic connection. The target pipe is 48.26 mm in outer diameter and 2.77 mm-thick. A single path welding without filler materials is required to reduce the weld heat input related to re-weldability. For the laser welding, the focal spot diameter was expanded to increase allowable misalignment. The TIG welding tool was equipped with AVC (Arc Voltage Control) to avoid a torch sticking and to enlarge allowable misalignment. For each tool, the welding conditions were optimized for all position welding to horizontally located pipes. Obtained parameters such as the weld heat input, allowable misalignment, lifetime of the tools and amount of sputter and fume, were comparatively assessed.
Shigematsu, Soichiro; Tanigawa, Hisashi; Aburadani, Atsushi; Takeda, Nobukazu; Kakudate, Satoshi; Mori, Seiji*; Nakahira, Masataka*; Raffray, R.*; Merola, M.*
Fusion Engineering and Design, 87(7-8), p.1218 - 1223, 2012/08
Times Cited Count:6 Percentile:43.19(Nuclear Science & Technology)The current design of the ITER blanket system is a modular configuration and a total of 440 blanket modules are to be installed in the ITER vacuum vessel. Each blanket module consists of the first wall (FW) and the shield block (SB). The FW receives a high heat load from the plasma. The SB shields components from the neutrons generated by the nuclear fusion reaction. The FW will be damaged by the heat load and neutrons, so it requires scheduled replacement. For the FW replacement, cutting/welding tools for the cooling pipes must be able to conduct the following operations: access and cut/weld the pipe from the inside of the cooling pipe. The cutting tool for the pipe end is required to cut flat plate circularly from the surface side of the FW. This paper describes the current status of R&D of the cutting tools for maintenance of the cooling pipe of the FW.
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
Times Cited Count:14 Percentile:64.80(Physics, Nuclear)Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; et al.
Nuclear Physics A, 805(1-4), p.257 - 259, 2008/06
no abstracts in English
Shizuma, Toshiyuki; Ishii, Tetsuro; Makii, Hiroyuki*; Hayakawa, Takehito; Matsuda, Makoto; Shigematsu, Soichiro*; Ideguchi, Eiji*; Zheng, Y.*; Liu, M.*; Morikawa, Tsuneyasu*; et al.
Physical Review C, 77(4), p.047303_1 - 047303_4, 2008/04
Times Cited Count:10 Percentile:55.96(Physics, Nuclear)Modest spin states in neutron-rich W have been populated using a
W(
O,
O) one-neutron transfer reaction. While negative-parity bands previously known are extended to higher spin, two positive-parity bands are newly identified. Configurations based on
i
orbitals are assigned to these bands from an analysis of the level energy systematics as well as the g-factors derived from in-band branching ratios.
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
Times Cited Count:28 Percentile:83.33(Physics, Nuclear)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.
Shizuma, Toshiyuki; Ishii, Tetsuro; Makii, Hiroyuki; Hayakawa, Takehito; Shigematsu, Soichiro*; Matsuda, Makoto; Ideguchi, Eiji*; Zheng, Y.*; Liu, M.*; Morikawa, Tsuneyasu*
European Physical Journal A, 34(1), p.1 - 4, 2007/10
Times Cited Count:7 Percentile:49.96(Physics, Nuclear)Excited states in neutron-rich Ta have been populated following the one-proton pickup reaction of
W(
O,
F). In-beam
rays were measured in coincidence with scattered particles detected by a high-resolution
-
Si telescope for reaction channel selection. Several low-lying levels including a
s isomer at 406 keV have been identified. A spin assignment of
and the 1/2
[411] Nilsson configuration are given to the isomer in comparison with the level energy systematics and the isomer decay rates in the region.
Ishii, Tetsuro; Shigematsu, Soichiro*; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.
Physics of Atomic Nuclei, 70(8), p.1457 - 1461, 2007/08
Times Cited Count:9 Percentile:56.22(Physics, Nuclear)We have measured deexcitation rays in the neutron-rich nuclei of
U,
Pu and
Cm. These nuclei were produced by the (
O,
O) two-neutron transfer reactions with a 200, 162 and 162 MeV
O beams and a
U,
Pu and
Cm targets, respectively, using the tandem accelerator at Tokai, Japan. The
rays in residual nuclei were measured by taking coincidence with scattering particles using Si
-
detectors. We have identified
rays in
U,
Pu and
Cm by selecting the kinetic energies of
O particles which correspond to the excitation energies in these nuclei below their neutron separation energies. The ground-state bands of
U,
Pu and
Cm were established up to 12
states and the
octupole band of
U was established up to 9
state. Because the deformations of these nuclei are well developed, the moments of inertia reflect the pairing gap, which is expected to be smaller, resulting in a larger moment of inertia, at the deformed shell closure. We have found that the moment of inertia of the ground-state band of
Cm
is considerably larger than that of
Cm
. This fact supports the existence of the deformed subshell closure at
in Cm isotopes. On the other hand, the moment of inertia of
Pu
was found to be smaller than that of
Pu
, which suggests that the deformed subshell closure at
weakens or disappears in Pu isotopes. These results are consistent with the prediction by a cranking model calculation.
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
Times Cited Count:14 Percentile:67.70(Physics, Nuclear)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.
Shizuma, Toshiyuki; Ishii, Tetsuro; Makii, Hiroyuki; Hayakawa, Takehito; Shigematsu, Soichiro; Matsuda, Makoto; Ideguchi, Eiji*; Zheng, Y.*; Liu, M.*; Morikawa, Tsuneyasu*; et al.
European Physical Journal A, 30(2), p.391 - 396, 2006/11
Times Cited Count:12 Percentile:61.31(Physics, Nuclear)Excited states in neutron-rich W have been populated using a
W(
O,
O) reaction. In-beam
rays were measured in coincidence with scattered particles detected by a high-resolution
-
Si telescope. In this experiment, the ground state band has been identified up to
. The
band, the
octupole band, and a 2-quasiparticle state were also observed. The results are compared with predictions of self-consistent HFB cranking calculations and blocked-BCS multi-quasiparticle calculations.
Ishii, Tetsuro; Shigematsu, Soichiro; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; Kaneko, Junichi*; et al.
Journal of the Physical Society of Japan, 75(4), p.043201_1 - 043201_4, 2006/04
Times Cited Count:19 Percentile:68.29(Physics, Multidisciplinary)The ground-state band of the neutron-rich transuranium nucleus Cm was established up to spin 12 by in-beam
-ray spectroscopy using the two-neutron-transfer reaction with a
Cm target and a 162 MeV
O beam. Deexcitation
rays in
Cm were identified by selecting the kinetic energies of
O particles with Si
-
detectors. The moment of inertia of
Cm
is considerably smaller than that of
Cm
, which supports the existence of the deformed subshell closure at
in Cm isotopes.
Ishii, Tetsuro; Shigematsu, Soichiro; Asai, Masato; Makishima, Akiyasu*; Matsuda, Makoto; Kaneko, Junichi*; Hossain, I.*; Ichikawa, Shinichi; Kono, Toshiyuki*; Ogawa, Masao*
Physical Review C, 72(2), p.021301_1 - 021301_5, 2005/08
Times Cited Count:20 Percentile:76.26(Physics, Nuclear)In the two-neutron-transfer reaction of a 200-MeV O beam with a
U target, deexcitation
rays in a neutron-rich nucleus of
U were measured. The
rays in
U were identified by taking coincidence with
O, using Si
-
detectors. The kinetic energies of
O particles allowed us to select the excitation energies of
U below the neutron separation energy. The ground-state band and the
octupole band of
U were established up to 12
and 9
, respectively. The octupole-band head of
U is higher than those of
U by about a hundred keV, suggesting that a secondary maximum of octupole correlations exists at
in U isotopes.
Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Koura, Hiroyuki; Shigematsu, Soichiro*; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Shizuma, Toshiyuki; et al.
no journal, ,
The ground-state bands of Th,
U,
Pu and
Cm were established by measuring deexcitation
rays. These nuclei were produced by the (
O,
O) and (
O,
Ne) two-nucleon transfer reactions with
U,
Pu and
Cm targets. The
rays in residual nuclei were identified by taking coincidence with scattering particles using high-resolution Si
-
detectors. By extending the systematics of the 2
energies into neutron-rich nuclei, we have found that the
deformed shell gap disappears at
Pu isotopes and that U and Pu isotopes have the possibility of the spherical shell closure at
.
Shizuma, Toshiyuki; Ishii, Tetsuro; Makii, Hiroyuki; Hayakawa, Takehito; Shigematsu, Soichiro*; Matsuda, Makoto; Ideguchi, Eiji*; Zheng, Y.*; Liu, M.*; Morikawa, Tsuneyasu*; et al.
no journal, ,
Neutron-rich W-Os nuclei with exhibit the various signature of nuclear collective motions such as
-softness, triaxiality, and a prolate-oblate shape transition. In addition, the emergence of high-
isomers, where
is the angular momentum projection on the nuclear symmetry axis, based on multi-quasiparticle excitation is a characteristic of nuclei in this region. The recent experimental and theoretical studies of the neutron-rich W nuclei have revealed the existence of high-
multi-quasiparticle isomers. Here we report results from the in-beam
-ray spectroscopic experiments on neutron-rich
W and
W.
Ishii, Tetsuro; Makii, Hiroyuki; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Shizuma, Toshiyuki; Makishima, Akiyasu*; Tome, Hayato*; Shigematsu, Soichiro*; et al.
no journal, ,
no abstracts in English
Makii, Hiroyuki; Ishii, Tetsuro; Asai, Masato; Tsukada, Kazuaki; Toyoshima, Atsushi; Matsuda, Makoto; Makishima, Akiyasu*; Kaneko, Junichi*; Tome, Hayato; Ichikawa, Shinichi; et al.
no journal, ,
We have measured in-beam rays in the neutron-rich
Pu
and
Pu
nuclei by means of
Pu(
O,
O)
Pu and
Pu(
O,
O)
Pu neutron transfer reactions, respectively. The ground-state band of
Pu was established up to the
state. The systematics of the 2
energies for the ground-state bands of Pu isotopes suggests that the
deformed shell closure disappears in Pu. The measurement of deexcitation
rays in
Pu shows a small energy spacing between the neutron orbitals at
, which explains the disappearance of the shell closure.
Kakudate, Satoshi; Takeda, Nobukazu; Aburadani, Atsushi; Shigematsu, Soichiro; Matsumoto, Yasuhiro*; Tsuji, Koichi*
no journal, ,
Maintenance of the ITER blanket will be carried out in the vacuum vessel (VV) using remote handling equipment, including the in-vessel transporter (IVT) with vehicle type manipulators. An estimated 440 blanket modules, each with a maximum weight of 44.kN, will be installed in the VV. The ray dose rate is expected to be approximately 500 Gy/h during the periods of blanket maintenance. This paper describes the system integration of maintenance robot for ITER (International thermonuclear experimental reactor). This design items include design requirements, in-vessel transporter (maintenance robot) mechanism, installation mechanism and the rescue concept in case of failure mode.
Shigematsu, Soichiro; Aburadani, Atsushi; Takeda, Nobukazu; Kozaka, Hiroshi; Negishi, Yusuke; Kakudate, Satoshi
no journal, ,
no abstracts in English