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Kobayashi, Taishi*; Fushimi, Tomokazu*; Mizukoshi, Hirofumi*; Motokawa, Ryuhei; Sasaki, Takayuki*
Langmuir, 38(48), p.14656 - 14665, 2022/12
Times Cited Count：2 Percentile：27.64(Chemistry, Multidisciplinary)no abstracts in English
O
Yoshioka, Satoru*; Tsuruta, Konosuke*; Yamamoto, Tomokazu*; Yasuda, Kazuhiro*; Matsumura, Sho*; Sugiyama, Takeharu*; Oba, Yojiro; Ishikawa, Norito; Kobayashi, Eiichi*; Okudaira, Koji*
Journal of the American Ceramic Society, 103(8), p.4654 - 4663, 2020/08
Times Cited Count：4 Percentile：22.32(Materials Science, Ceramics)X-ray absorption near edge structure (XANES) and small-angle X-ray scattering (SAXS) reveal the damaged structures in MgAlO spinel induced by swift heavy ions. SAXS indicates the formation of ion tracks with cylindrical shape with a diameter of 5 nm. XANES indicates the cationic disordering between tetrahedral and octahedral sites by the irradiation. Quantitative analysis of XANES also reveals that cations preferably occupy the octahedral sites at high fluence.
O induced by swift heavy ionsYoshioka, Satoru*; Tsuruta, Konosuke*; Yamamoto, Tomokazu*; Yasuda, Kazuhiro*; Matsumura, Sho*; Ishikawa, Norito; Kobayashi, Eiichi*
Physical Chemistry Chemical Physics, 20(7), p.4962 - 4969, 2018/02
Times Cited Count：5 Percentile：22.84(Chemistry, Physical)Cationic disorder in the MgAlO spinel induced by swift heavy ions was investigated using the X-ray absorption near edge structure. With changes in the irradiation fluences of 200 MeV Xe ions, the Mg K-edge and Al K-edge spectra were synchronously changed. The calculated spectra based on density function theory indicate that the change in the experimental spectra was due to cationic disorder between Mg in tetrahedral sites and Al in octahedral sites. These results suggest a high inversion degree to an extent that the completely random configuration is achieved in MgAlO induced by the high density electronic excitation under swift heavy ion irradiation.
SGo, Shintaro*; Ideguchi, Eiji*; Yokoyama, Rin*; Kobayashi, Motoki*; Kisamori, Keiichi*; Takaki, Motonobu*; Miya, Hiroyuki*; Ota, Shinsuke*; Michimasa, Shinichiro*; Shimoura, Susumu*; et al.
JPS Conference Proceedings (Internet), 6, p.030005_1 - 030005_4, 2015/06
Ikeda, Yoshitaka; Okano, Fuminori; Sakasai, Akira; Hanada, Masaya; Akino, Noboru; Ichige, Hisashi; Kaminaga, Atsushi; Kiyono, Kimihiro; Kubo, Hirotaka; Kobayashi, Kazuhiro; et al.
Nihon Genshiryoku Gakkai Wabun Rombunshi, 13(4), p.167 - 178, 2014/12
The JT-60U torus was disassembled so as to newly install the superconducting tokamak JT-60SA torus. The JT-60U used the deuterium for 18 years, so the disassembly project of the JT-60U was the first disassembly experience of a fusion device with radioactivation in Japan. All disassembly components were stored with recording the data such as dose rate, weight and kind of material, so as to apply the clearance level regulation in future. The lessons learned from the disassembly project indicated that the cutting technologies and storage management of disassembly components were the key factors to conduct the disassembly project in an efficient way. After completing the disassembly project, efforts have been made to analyze the data for characterizing disassembly activities, so as to contribute the estimation of manpower needs and the radioactivation of the disassembly components on other fusion devices.
Ikeda, Yoshitaka; Okano, Fuminori; Hanada, Masaya; Sakasai, Akira; Kubo, Hirotaka; Akino, Noboru; Chiba, Shinichi; Ichige, Hisashi; Kaminaga, Atsushi; Kiyono, Kimihiro; et al.
Fusion Engineering and Design, 89(9-10), p.2018 - 2023, 2014/10
Times Cited Count：2 Percentile：16.35(Nuclear Science & Technology)Disassembly of the JT-60U torus was started in 2009 after 18-years D operations, and was completed in October 2012. The JT-60U torus was featured by the complicated and welded structure against the strong electromagnetic force, and by the radioactivation due to D-D reactions. Since this work is the first experience of disassembling a large radioactive fusion device in Japan, careful disassembly activities have been made. About 13,000 components cut into pieces with measuring the dose rates were removed from the torus hall and stored safely in storage facilities by using a total wokers of 41,000 person-days during 3 years. The total weight of the disassembly components reached up to 5,400 tons. Most of the disassembly components will be treated as non-radioactive ones after the clearance verification under the Japanese regulation in future. The assembly of JT-60SA has started in January 2013 after this disassembly of JT-60U torus.
Morita, Takami*; Niwa, Kentaro*; Fujimoto, Ken*; Kasai, Hiromi*; Yamada, Haruya*; Nishiuchi, Ko*; Sakamoto, Tatsuya*; Godo, Waichiro*; Taino, Seiya*; Hayashi, Yoshihiro*; et al.
Science of the Total Environment, 408(16), p.3443 - 3447, 2010/06
Times Cited Count：13 Percentile：32.9(Environmental Sciences)Iodine-131 (
I) was detected in brown algae collected off the Japanese coast. The maximum measured specific activity of I in brown algae was 0.37
0.010 Bq/kg-wet. Cesium-137 (
Cs) was also detected in all brown algal samples used in this study. There was no correlation between specific activities of I and Cs in these seaweeds. Low specific activity and minimal variability of Cs in brown algae indicated that past nuclear weapon tests were the source of Cs. Although nuclear power facilities are known to be pollution sources of I, there was no relationship between the sites where I was detected and the locations of nuclear power facilities. Most of the sites where I was detected were near big cities with large populations. On the basis of the results, we suggest that the likely pollution source of I, detected in brown seaweeds, is not nuclear power facilities, but nuclear medicine procedures.
C Discharge and its Contribution to Development of an Advanced MethodKoarashi, Jun; Isaka, Keisuke*; Yokota, Tomokazu*; Kozawa, Tomoyasu*; Mikami, Satoshi; Akiyama, Kiyomitsu; Kobayashi, Hirohide
JNC TN8410 2005-005, 55 Pages, 2005/05
Some investigations were made for re-evaluating collection and measurement techniques in an airborne C discharge monitoring at the Tokai reprocessing plant (TRP), which include (1)collection efficiency of CO in a carbon sampler using monoethanolamine as CO absorbent;(2)affect of incorporating tritiated water into the carbon sampler on quantitative estimation of C activity in airborne effluent; (3)affect of leakage in air sampling on evaluating airborne C discharge; and (4)determination of chemical forms of C in airborne release from the TRP. The results presented not only the validity of the TRP's monitoring method, but also the technical aspects required for establishing a more reliable and effective monitoring method.
H Discharge and its Contribution to Development of an Advanced MethodKoarashi, Jun; Yokota, Tomokazu*; Kozawa, Tomoyasu*; Isaka, Keisuke*; Mikami, Satoshi; Akiyama, Kiyomitsu; Kobayashi, Hirohide
JNC TN8410 2005-004, 73 Pages, 2005/05
JNC-TN8410-2005-004.pdf:2.48MB
Some investigations were made for re-evaluating collection and measurement techniques in an airborn H discharge monitoring at the Tokai reprocessing plant (TRP), which include (1)collection efficiency of water in a tritium sampler; (2)quench correction in H activity measurement by liquid scintillation counting; (3)affect of leakage in air sampling on evaluating airborne H discharge; and (4)determination of chemical forms of H in airborne release from the TRP. The results presented not only the validity of the TRP's monitoring method, but also the technical aspects required for establishing a more reliable and effective monitoring method.
Motohashi, Yoshinobu*; Kobayashi, Tomokazu*; Harjo, S.*; Sakuma, Takaaki*; Shibata, Taiju; Ishihara, Masahiro; Baba, Shinichi; Hoshiya, Taiji
Nuclear Instruments and Methods in Physics Research B, 206, p.144 - 147, 2003/05
Times Cited Count：4 Percentile：33.7(Instruments & Instrumentation)The 3mol% yttria containing tetragonal zirconia polycrystals(3Y-TZP) were irradiated using 130MeV Zr
ions in the TANDEM accelerator facility at Tokai Research Establishment, JAERI. Irradiation was performed with the fluence of 3.5
10
and 2.110
ions/m
. Residual stress and changes in mechanical properties caused by the ion irradiation and the effects of the subsequent annealing are studied. The occurrence of compressive residual stresses and increases in hardness and fracture toughness were found at the surface regions of as-irradiated specimens. It was found from the subsequent annealing that these quantities decreased gradually with raising the annealing temperature and returned to that of un-irradiated state at around 1173K. A most probable cause of the increases in the hardness and fracture toughness after the irradiation may, therefore, be the residual compressive stresses left in the irradiated surface region.
Shibata, Taiju; Ishihara, Masahiro; Motohashi, Yoshinobu*; Baba, Shinichi; Hoshiya, Taiji; Kobayashi, Tomokazu*; Harjo, S.*; Sakuma, Takaaki*
Nuclear Instruments and Methods in Physics Research B, 206, p.139 - 143, 2003/05
Times Cited Count：4 Percentile：33.7(Instruments & Instrumentation)no abstracts in English
Sakuma, Takaaki*; Motohashi, Yoshinobu*; Kobayashi, Tomokazu*; Harjo, S.*; Shibata, Taiju; Ishihara, Masahiro; Baba, Shinichi; Hoshiya, Taiji
Nihon Kikai Gakkai Kanto Shibu Ibaraki Koenkai (2002) Koen Rombunshu (No.020-3), p.125 - 126, 2002/09
no abstracts in English
Kobayashi, Kaoru*; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Hino, Ryutaro
JAERI-Review 2002-010, 52 Pages, 2002/05
JAERI-Review-2002-010.pdf:3.38MB
no abstracts in English
Kobayashi, Kaoru*; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Teshigawara, Makoto; Hino, Ryutaro
JAERI-Tech 2002-005, 118 Pages, 2002/02
JAERI-Tech-2002-005.pdf:9.71MB
In order to examine the radiation safety of a spallation mercury target system, it is necessary to clarify the chemical forms of spallation products generated by spallation reaction with proton beam. As for the chemical forms of spallation products in mercury that involves large amounts of spallation products, these forms were estimated by using the binary phase diagrams and the thermochemical equilibrium calculation based on the amounts of spallation product. Calculation results showed that the mercury would dissolve Al, As, B, Be, Bi, C, Co, Cr, Fe, Ga, Ge, Ir, Mo, Nb, Os, Re, Ru, Sb, Si, Ta, Tc, V and W in the element state, and Ag, Au, Ba, Br, Ca, Cd, Ce, Cl, Cs, Cu, Dy, Er, Eu, F, Gd, Hf, Ho, I, In, K, La, Li, Lu, Mg, Mn, Na, Nd, Ni, O, Pb, Pd, Pr, Pt, Rb, Rh, S, Sc, Se, Sm, Sn, Sr, Tb, Te, Ti, Tl, Tm, Y, Yb, Zn and Zr in the form of inorganic mercury compounds.
Wan, C.*; Kobayashi, Tomokazu*; Motohashi, Yoshinobu*; Sakuma, Takaaki*; Ishihara, Masahiro; Shibata, Taiju
Ibaraki Daigaku Kogakubu Kenkyu Shuho, 49, p.69 - 79, 2002/02
no abstracts in English
Kaminaga, Masanori; Haga, Katsuhiro; Aso, Tomokazu; Kinoshita, Hidetaka; Kogawa, Hiroyuki; Ishikura, Shuichi*; Terada, Atsuhiko*; Kobayashi, Kaoru*; Adachi, Junichi*; Teraoku, Takuji*; et al.
Proceedings of American Nuclear Society Conference "Nuclear Applications in the New Millennium" (AccApp-ADTTA '01) (CD-ROM), 9 Pages, 2002/00
no abstracts in English
Kobayashi, Kaoru*; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Kogawa, Hiroyuki; Hino, Ryutaro
JAERI-Data/Code 2000-037, 69 Pages, 2000/12
JAERI-Data-Code-2000-037.pdf:3.21MB
no abstracts in English
Kobayashi, Kaoru*; Kaminaga, Masanori; Haga, Katsuhiro; Kinoshita, Hidetaka; Aso, Tomokazu; Kogawa, Hiroyuki; Hino, Ryutaro
JAERI-Tech 2000-050, 43 Pages, 2000/08
JAERI-Tech-2000-050.pdf:2.36MB
no abstracts in English
-rays from Am-241 in airborne effluentIto, Yasuhisa; Mikami, Satoshi; Miyauchi, Toru; Akiyama, Kiyomitsu; Kobayashi, Hirohide; Kozawa, Tomoyasu*; Yokota, Tomokazu*
no journal, ,
no abstracts in English
