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Sakai, Kenji; Sakamoto, Shinichi; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Kasugai, Yoshimi; Tatsumoto, Hideki; et al.
JAEA-Technology 2011-039, 121 Pages, 2012/03
JAEA-Technology-2011-039.pdf:10.87MB
This report investigates the behavior, damage and restoration of a neutron source station of the MLF at the Great East Japan Earthquake and verified the safety design for emergency accidents in the neutron source station. In the MLF, after an occurrence of the Earthquake, strong quakes were detected at the instruments, the external power supply was lost, all of the circulators shut down automatically, and the hydrogen gas was released. The leakages of mercury, hydrogen and radio-activation gases did not occur. While, the quakes made gaps between the shield blocks and ruptured external pipe lines by subsidence around the building. But significant damages to the components were not found though the pressure drop of compressed air lines influenced on a target trolley lock system and so on. These results substantiated the validity of the safety design for emergency accidents in the source station, and suggested several points of improvement.
Sakai, Kenji; Futakawa, Masatoshi; Takada, Hiroshi; Sakamoto, Shinichi; Maekawa, Fujio; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; et al.
Proceedings of 20th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-20) (USB Flash Drive), 6 Pages, 2012/03
This report investigates behaviors and damages of each component in a neutron target station of the MLF at the J-PARC at the time of the Great East Japan Earthquake (GEJE). At the date of the GEJE, in the MLF, strong quakes were detected at several instruments, an external power supply were lost, all of the circulation systems were shut down automatically, and a hydrogen gas was released as planned. Leakage of activation liquids and gases did not occur. While, the quakes made gaps between shield blocks and ruptured external pipe lines for air and water by subsidence. But significant damages on the components of the target station were not found though a loss of compressed air supply affected lock systems with air cylinders and pneumatic operation values. These results substantiated a validity of safety design on the target station for emergency accidents.
Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Yamakawa, Koichi; Miyanaga, Noriaki*
Optics Express (Internet), 17(10), p.7744 - 7749, 2009/05
Times Cited Count：13 Percentile：54.22(Optics)Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.
Kogawa, Hiroyuki; Ishikura, Shuichi*; Sato, Hiroshi; Harada, Masahide; Takatama, Shunichi*; Futakawa, Masatoshi; Haga, Katsuhiro; Hino, Ryutaro; Meigo, Shinichiro; Maekawa, Fujio; et al.
Journal of Nuclear Materials, 343(1-3), p.178 - 183, 2005/08
Times Cited Count：8 Percentile：49.16(Materials Science, Multidisciplinary)A cross-flow type (CFT) mercury target with flow guide blades, which has been developed for JSNS, can suppress the generation of stagnant flow region especially near the beam window where the peak heat density is generated due to spallation reaction. Then, a flat type beam window has been applied to the CFT target from the viewpoint of suppressing dynamic stress caused by a pressure wave, which has been estimated with a mercury model of the linear equation of state. The recent experimental results obtained by using a proton beam incidents to mercury led that a cutoff pressure model in the equation of state of mercury caused a suitable dynamic stress with experimental results. Dynamic stress analyses were carried out with the cutoff pressure model, in which the negative pressure less than 0.15 MPa was not generated. The generated dynamic stress in the flat beam window became much larger than that in a semi-cylindrical type window. However, the generated stress in the semi-cylindrical type beam window was over the allowable stress of SS316L under the peak heat density of 668 W/cc. In order to decrease the dynamic stress in the semi-cylindrical beam window, the incident proton beam was defocused to decrease the peak heat density down to 218 W/cm
. As a result, the dynamic stress could be suppressed less than the allowable stress. On the other hand, due to defocus of the proton beam, high heat density was generated on the end of the flow guide blades, which caused high thermal stress exceeding the allowable stress. To decrease the thermal stress, several shapes of the blade ends were studied analytically, which were selected so as not to affect the mercury flow distribution. A simple thin-end blade showed low thermal stress below the allowable stress.
Ishikura, Shuichi*; Futakawa, Masatoshi; Kogawa, Hiroyuki; Meigo, Shinichiro; Maekawa, Fujio; Harada, Masahide; Sato, Hiroshi; Haga, Katsuhiro; Ikeda, Yujiro
JAERI-Tech 2004-028, 123 Pages, 2004/03
JAERI-Tech-2004-028.pdf:9.55MB
This report describes the structural design concept applied to the mercury target vessel used for the spallation neutron source installed in the material and life science experiment facility of J-PARC (Japan Proton Accelerator Complex), and the results evaluated on the basis of the concept. The features of the design concept are as follows: (1) The target vessel design is followed to "Law concerning Prevention from Radiation Hazards due to Radio-Isotopes". That is because (i) there is not the possibility in the target of the RIA (Reactivity Initiated Accident) generally considered in the nuclear power reactors, and (ii) the target vessel is not a permanent structure. (2) Therefore, the Class 1 Vessel of the JIS B-8270 [design code for pressure vessel] that is equivalent to a standard for nuclear power structural design is applicable as a design code for the target to sufficiently keep the safety of target system. The stresses for the design were evaluated using the linear elastic analysis based on the infinitesimal strain theory in order to confirm the safe and rational design.
Kogawa, Hiroyuki; Ishikura, Shuichi*; Hino, Ryutaro; Kato, Takashi; Aso, Tomokazu; Sato, Hiroshi; Harada, Masahide; Kai, Tetsuya; Teshigawara, Makoto; Maekawa, Fujio; et al.
Proceedings of ICANS-XVI, Volume 2, p.635 - 644, 2003/07
no abstracts in English
Mukai, Takahiro*; Ogawa, Kazuma*; Arano, Yasushi*; Ono, Masahiro*; Fujioka, Yasushi*; Izumo, Mishiroku; Konishi, Junji*; Saji, Hideo*
Journal of Labelled Compounds and Radiopharmaceuticals, 44(Suppl.1), p.S617 - S618, 2001/05
no abstracts in English
Ogawa, Kazuma*; Ono, Masahiro*; Fujioka, Yasushi*; Saji, Hideo*; Mukai, Takahiro*; Konishi, Junji*; Uehara, Tomoya*; Arano, Yasushi*; Onoma, Katsuyuki
Kaku Igaku, 37(5), P. 577, 2000/09
no abstracts in English
Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Yamakawa, Koichi; Miyanaga, Noriaki*
no journal, ,
Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.
Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Miyanaga, Noriaki*; Yamakawa, Koichi
no journal, ,
Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.
Ogawa, Kanade; Sueda, Keiichi*; Akahane, Yutaka; Aoyama, Makoto; Tsuji, Koichi; Fujioka, Kana*; Kanabe, Tadashi*; Miyanaga, Noriaki*; Yamakawa, Koichi
no journal, ,
Using a partially deuterated KDP crystal for an optical parametric amplifier, we demonstrated ultrabroadband optical parametric chirped-pulse amplification of more than 250 nm bandwidth at a center wavelength of 1050 nm. We numerically show how to control the broadband phase matching conditions at different wavelengths to match center wavelengths of suitable broadband seed sources by adjusting the deuteration level in partially deuterated KDP.
Kaneko, Naoaki*; Otani, Akihito*; Waki, Minoru*; Ogawa, Fujio*; Tsukimori, Kazuyuki
no journal, ,
no abstracts in English
Oikawa, Kenichi; Takada, Hiroshi; Ogawa, Akira; Tanaka, Hiromichi; Maekawa, Fujio
no journal, ,
Japan Spallation Neutron Source provides 23 beam-lines for the neutron experiments in MLF, and each beam-line has an independent primary shutter. Meanwhile, the SNS at U.S. has 24 beam-lines, but they have 12-single channel shutter blocks and 6-multichannel shutter blocks. We realized independent shutter operation for every instrument in JSNS by proper shielding design of the target station and a compact mechanical design of the driving system of the primary shutter. We summarize the status of JSNS shutter system from May 2008 to July 2012 operation, some trouble and their recovery work. In addition, we are facing a Single Event Effect due to the high-energy neutron at the encoder of the servo-moter system. Upcoming improvement in next year will be presented.
Wan, T.; Kogawa, Hiroyuki; Obayashi, Hironari; Iwamoto, Hiroki; Takei, Hayanori; Sasa, Toshinobu; Maekawa, Fujio
no journal, ,
