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Uchiyama, Naoki*; Ozawa, Tatsuya*; Sato, Koji*; Kobayashi, Jun; Onojima, Takamitsu; Tanaka, Masaaki
FAPIG, (194), p.12 - 18, 2018/02
no abstracts in English
As using high-resolution inelastic X-ray scatteringMurai, Naoki*; Fukuda, Tatsuo; Kobayashi, Tatsuya*; Nakajima, Masamichi*; Uchiyama, Hiroshi*; Ishikawa, Daisuke*; Tsutsui, Satoshi*; Nakamura, Hiroki; Machida, Masahiko; Miyasaka, Shigeki*; et al.
Physical Review B, 93(2), p.020301_1 - 020301_5, 2016/01
Times Cited Count：7 Percentile：34.12(Materials Science, Multidisciplinary)Uchiyama, Naoki
FAPIG, (174), p.5 - 10, 2007/02
The operation of Proto-type Fast Breeder Reactor MONJU has been suspended since December 1995, due to the sodium leak accident at the secondary cooling system. The construction work for sodium leak event is progressing from September 2005, to solve the problems pointed out in the general safety investigation of MONJU carried out after this accident. 90% of the construction work was completed at the end of December 2006. The confirmation test was already started from December 18, 2006. This report describes the present status of MONJU, mainly about the progress and results of the construction work performed by Fuji Electric Systems co., Ltd. and Kawasaki Plant Systems, Ltd.
Fujine, Sachio; Murata, Mikio; Abe, Hitoshi; Takada, Junichi; Tsukamoto, Michio; Miyata, Teijiro*; Ida, Masaaki*; Watanabe, Makio; Uchiyama, Gunzo; Asakura, Toshihide; et al.
JAERI-Research 99-056, p.278 - 0, 1999/09
JAERI-Research-99-056.pdf:22.73MB
no abstracts in English
Uchiyama, Naoki; Takai, Toshihide; Nishimura, Masahiro; Miyahara, Shinya; Miyake, Osamu; Tanabe, Hiromi
PNC TN9410 97-051, 383 Pages, 1997/03
As a part of the work for investigating the sodium leak accident which occurred in Monju, sodium fire test-II was carried out using SOLFA-1 (Sodium Leak, Fire and Aerosol) facility at OEC/PNC. In the test, the piping, ventilation duct, grating and floor liner were an full-sized and arranged in a rectangular concrete cell in the same manner as Monju. Main objectives of the test are to confirm leak and burming behavior of sodium from the damaged thermometer, and effects of the sodium fire on integrity of the surrounding structure, etc. The main conclusions obtained from the test are shown as below. (1)Burning Behavior of Leaked Sodium : Images taken with cameras in the test reveal that in the early stages of the sodium leak, the sodium dropped down out of the flexible tube in drips. This dripping and burning were expanded in range as the sodium splashed on the duct, the grating and a support of thermocouples for the measurement of gas temperature. (2)Damage of Ventilation Duct and Grating : The temperature of the ventilation duct's inner surface fluctuated between approximately 600
C and 700C. The temperature of the grating began rising at the outset of the test, then fluctuated between roughly 600C and 900C. The maximum temperature was about 1000C. After the test, damage of the ventilation duct and the grating was found. Damage of the duct was greater than that of Monju. (3)Effects on Floor Liner : The temperature of the floor liner under the leak point exceeded 1,000C at 3 hours and 20 minutes of the test; Post test inspection of the liner revealed five holes in the region of about 1m 
1m under the leak point. There was also a decrease of a liner thickness on the north side and west side of the leak point. (4)Effects on Concrete : No surface damage of the concrete side walls and ceiling was found by the post test inspection. The floor concrete was eroded by a depth of 8 cm at maximum due to ...
As via inelastic X-ray scatteringMurai, Naoki*; Fukuda, Tatsuo; Uchiyama, Hiroshi*; Tsutsui, Satoshi*; Ishikawa, Daisuke*; Kobayashi, Tatsuya*; Nakamura, Hiroki; Machida, Masahiko; Nakajima, Masamichi*; Miyasaka, Shigeki*; et al.
no journal, ,
no abstracts in English
Co
)As by inelastic X-ray scatteringMurai, Naoki*; Fukuda, Tatsuo; Nakajima, Masamichi*; Kobayashi, Tatsuya*; Uchiyama, Hiroshi*; Tsutsui, Satoshi*; Ishikawa, Daisuke*; Nakamura, Hiroki; Machida, Masahiko; Miyasaka, Shigeki*; et al.
no journal, ,
As via high-resolution inelastic X-ray scatteringMurai, Naoki; Fukuda, Tatsuo; Kobayashi, Tatsuya*; Nakajima, Masamichi*; Uchiyama, Hiroshi*; Ishikawa, Daisuke*; Tsutsui, Satoshi*; Nakamura, Hiroki; Machida, Masahiko; Miyasaka, Shigeki*; et al.
no journal, ,
We report the first IXS study of single crystals of SrFeAs that have been detwinned via application of in-plane uniaxial stress. Our results clearly show anisotropy in phonon structure below 
= 
characterized by mode splitting at tetragonally-equivalent momentum transfers. To the best of our knowledge, this is the first observation of phonon anisotropy in iron-pnictides at finite momentum transfers. We obtain good agreement with our results using calculations that are modified to account for a reduced magnetic moment and fluctuating magnetism. Previous efforts using either non-magnetic calculations or static magnetism tend to either get the dispersion wrong from non-magnetic calculations or strongly over-estimate the phonon mode splitting when static magnetism is included. Our model for the response below incorporates a phenomenological reduction in force constant anisotropy, by about 65%, that can be attributed to residual fast magnetic fluctuations. Above , all fluctuations are assumed to be fast and the response becomes the average of the results from the static magnetism. This serves as a starting point for a general model of phonons in iron-pnictides applicable to both non-magnetic and magnetic phases.
