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Kumagai, Yuta; Nagaishi, Ryuji; Kimura, Atsushi*; Taguchi, Mitsumasa*; Nishihara, Kenji; Yamagishi, Isao; Ogawa, Toru
Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.37 - 45, 2021/10
Zeolite adsorbents are to be used for decontamination of radioactive water in Fukushima Dai-ichi Nuclear Power Station. Evaluation of hydrogen production by water radiolysis during decontamination is important for safe operation. Thus hydrogen production from the mixture of zeolite adsorbents and seawater was studied because seawater was urgently used as a coolant for the fuels. The hydrogen yield from the mixture decreased at a high weight fraction of zeolites. However, the measured yield was higher than the yield expected from the direct radiolysis of seawater in the mixture, which would decrease proportional to the weight fraction of seawater. The result suggests that the radiation energy deposited to zeolites was involved in the hydrogen formation. From the results, the hydrogen production rate was evaluated to be 3.6 mL/h per ton of radioactive water before decontamination. After the process, it was evaluated to be 1.5 L/h per ton of waste adsorbents due to the high dose rate.
Taguchi, Shigeo; Yamamoto, Masahiko; Furuse, Takahiro*; Masaki, Yuji*; Kuno, Takehiko
JAEA-Technology 2018-005, 14 Pages, 2018/06
JAEA-Technology-2018-005.pdf:0.94MB
The method to remove Pu, Am and Np from plutonium nitrate solution recovered from spent nuclear fuel prior to ICP-OES measurement has been developed for the determination of 18 impurity metal elements (Fe, Cr, Ni, Mn, Al, Cd, V, Cu, Si, Zn, Mo, Sn, Ca, Mg, Na, Ag, Pb, B). In this method, two TRU resin packed columns were used for separation. In the first column, Pu and Am were mainly removed by adsorption. The recovered solution from the fist column was added to the second column after reduction of Np, and Am(III) and Np(IV) were removed by adsorption. The Pu nitrate solution (22g/L) of 2mL were treated by proposed method. The alpha emission nuclide was decreased to 
5.8 Bq/mL in a solution diluted to 100mL. As a result of ICP-OES measurement, the recoveries of impurity metals separated by proposed method were almost 100%. This separation scheme can apply to the metal impurity elemental analysis in Pu nitrate solution recovered from spent nuclear fuel.
Awual, M. R.; Miyazaki, Yuji; Taguchi, Tomitsugu; Shiwaku, Hideaki; Yaita, Tsuyoshi
Chemical Engineering Journal, 291, p.128 - 137, 2016/05
Times Cited Count：228 Percentile：99.33(Engineering, Environmental)Awual, M. R.; Yaita, Tsuyoshi; Miyazaki, Yuji; Matsumura, Daiju; Shiwaku, Hideaki; Taguchi, Tomitsugu
Scientific Reports (Internet), 6, p.19937_1 - 19937_10, 2016/01
Times Cited Count：182 Percentile：97.55(Multidisciplinary Sciences)
-radiation effect on solvent extraction of minor actinideSugo, Yumi; Sasaki, Yuji; Taguchi, Mitsumasa; Ishioka, Noriko
Journal of Radioanalytical and Nuclear Chemistry, 303(2), p.1381 - 1384, 2015/02
Times Cited Count：4 Percentile：25.85(Chemistry, Analytical)
radiolysis of the mixture of mordenite and seawaterKumagai, Yuta; Kimura, Atsushi; Taguchi, Mitsumasa; Nagaishi, Ryuji; Yamagishi, Isao; Kimura, Takaumi
Journal of Nuclear Science and Technology, 50(2), p.130 - 138, 2013/02
Times Cited Count：29 Percentile：90.21(Nuclear Science & Technology)Isobe, Kanetsugu; Alimov, V. Kh.*; Taguchi, Akira*; Saito, Makiko; Torikai, Yuji*; Hatano, Yuji*; Yamanishi, Toshihiko
Journal of Plasma and Fusion Research SERIES, Vol.10, p.81 - 84, 2013/02
The distribution of hydrogen trapping sites on W surface exposed with D plasma was examined by the techniques of imaging plate and autoradiography. Recrystallized W specimens were exposed with D plasma at around 495 and 550 K to the same fluence of 10
D/m
. Then, tritium was introduced into specimen by the exposure to tritium gaseous at 473 K. After that, the tritium distribution on W surface was examined by the techniques of imaging plate and autoradiography. From the results of the imaging plate, tritium was found to be highly concentrated within the area exposed with D plasma and the concentration of tritium was slightly varied even in that area. In the autoradiograph of W surface, it was found that tritium concentrated on the grain boundary and blisters.
Sugo, Yumi; Taguchi, Mitsumasa; Sasaki, Yuji; Morita, Yasuji; Ishioka, Noriko
JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 18, 2013/01
Yamazaki, Tatsuya; Asaoka, Hidehito; Taguchi, Tomitsugu; Yamamoto, Shunya; Yamazaki, Dai; Maruyama, Ryuji; Takeda, Masayasu; Shamoto, Shinichi
Thin Solid Films, 520(8), p.3300 - 3303, 2012/02
Times Cited Count：2 Percentile：10.02(Materials Science, Multidisciplinary)We succeeded in realizing the epitaxial growth of a Sr layer on Si(111) with an atomically abrupt heterointerface - in spite of its large lattice mismatch (12%) with Si - by introducing a monoatomic layer of H on Si. In order to identify the buried H, we carried out a combination analysis involving neutron reflectometry and resonant nuclear reaction of 
H(
N,)
C analysis. We found different neutron reflectivity profiles resulting from a contrast variation between the H and D atoms at the buried heterointerface. Furthermore, the depth -ray intensity profiles revealed that the H at the heterointerface acts as an effective buffer layer that enables it to manage the highly mismatched epitaxy on Si.
Fukada, Satoshi*; Edao, Yuki*; Sato, Koichi*; Takeishi, Toshiharu*; Katayama, Kazunari*; Kobayashi, Kazuhiro; Hayashi, Takumi; Yamanishi, Toshihiko; Hatano, Yuji*; Taguchi, Akira*; et al.
Fusion Engineering and Design, 87(1), p.54 - 60, 2012/01
Times Cited Count：4 Percentile：31.96(Nuclear Science & Technology)An experimental study on tritium (T) transfer in porous concrete for the tertiary T safety containment is performed to investigate (1) how fast HTO penetrates through concrete walls, (2) how well concrete walls contaminated with water-soluble T are decontaminated by a solution-in-water technique, and (3) how well hydrophobic paint coating works as a protecting film against HTO migrating through concrete walls. The epoxy paint coating can work as a HTO diffusion barrier and the PRF value is around 1/10. The silicon paint coating cannot work as the anti-T permeation barrier, because water deteriorates contact between the paint and cement or mortar.
-dodecaneSugo, Yumi; Taguchi, Mitsumasa; Sasaki, Yuji; Morita, Yasuji
JAEA-Review 2011-043, JAEA Takasaki Annual Report 2010, P. 18, 2012/01
Kumagai, Yuta; Nagaishi, Ryuji; Kimura, Atsushi; Taguchi, Mitsumasa; Nishihara, Kenji; Yamagishi, Isao; Ogawa, Toru
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.235 - 239, 2011/12
Zeolite adsorbents are to be used for decontamination of radioactive water in Fukushima Dai-ichi Nuclear Power Station. Evaluation of hydrogen production by water radiolysis during decontamination is important for safe operation. Thus hydrogen production from the mixture of zeolite adsorbents and seawater was studied because seawater was urgently used as a coolant for the fuels. The hydrogen yield from the mixture decreased at a high weight fraction of zeolites. However, the measured yield was higher than the yield expected from the direct radiolysis of seawater in the mixture, which would decrease proportional to the weight fraction of seawater. The result suggests that the radiation energy deposited to zeolite is involved in the hydrogen formation. From the results, the hydrogen production rate was evaluated to be 3.6 mL/h per ton of radioactive water before decontamination. After the process, it was evaluated to be 1.5 L/h per ton of waste adsorbents due to the high dose rate.
Sugo, Yumi; Taguchi, Mitsumasa; Sasaki, Yuji; Hirota, Koichi; Morita, Yasuji
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 17, 2011/01
Kimura, Atsushi; Taguchi, Mitsumasa; Kondo, Takafumi*; Yang, J.*; Nagaishi, Ryuji; Yoshida, Yoichi*; Hirota, Koichi
Radiation Physics and Chemistry, 79(11), p.1159 - 1164, 2010/11
Times Cited Count：3 Percentile：24.08(Chemistry, Physical)Much of this past research has focused on finding more effective reactions between charged reactive species in room temperature ionic liquid (RTILs), which have a coulombic field. Reactions in RTILs involving the charged reactive species, particularly solvated electrons, have been studied by the techniques of radiation chemistry. The reaction behavior of halophenols in RTILs were investigated by ray and pulsed electron radiolysis. The yield of CP decomposition in the RTILs was almost the same as that of solvated electrons formation. The yield of CP decomposition and phenol formation in the RTILs was low in the presence of electron scavengers such as nitrous oxide, indicating that solvated electrons primarily contributed to the decomposition of CP. The type of halogen group with the exception of fluorine had a negligible effect on the decomposition of halophenols in the RTILs. Therefore, RTILs could be applied as an reaction media for the reduction by ionizing radiation.
-dodecaneSugo, Yumi; Taguchi, Mitsumasa; Sasaki, Yuji; Morita, Yasuji
Proceedings of 3rd Asia-Pacific Symposium on Radiation Chemistry (APSRC 2010) and DAE-BRNS 10th Biennial Trombay Symposium on Radiation & Photochemistry (TSRP 2010) (CD-ROM), p.34 - 35, 2010/09
Sugo, Yumi; Taguchi, Mitsumasa; Nagaishi, Ryuji; Sasaki, Yuji; Hirota, Koichi; Morita, Yasuji
JAEA-Review 2009-041, JAEA Takasaki Annual Report 2008, P. 26, 2009/12
The radiolytic stabilities of the organic extractants for the separation of actinides have been commonly evaluated by the irradiation with -rays as the most convenient method. However in the actual partitioning process of HLW, the extractants will be exposed to alpha-particles emitted from actinides, as well as beta- and -rays from various fission products. In this study, alpha-radiolysis of 
-tetraoctyldiglycolamide (TODGA) in -dodecane was investigated by the irradiation with helium ion beam accelerated by a tandem accelerator using the TC1 irradiation apparatus in the TIARA facility. The sample was also irradiated with 
Co -rays for comparison of the radiation chemical yields between - and -rays. It was found that TODGA had almost fourfold resistance to -rays, as compared with -rays. This result suggests that the radiolytic degradation of TODGA has been hitherto overestimated only by the irradiation with -rays.
Sugo, Yumi; Taguchi, Mitsumasa; Sasaki, Yuji; Hirota, Koichi; Kimura, Takaumi
Radiation Physics and Chemistry, 78(12), p.1140 - 1144, 2009/12
Times Cited Count：31 Percentile：87.31(Chemistry, Physical)In the actual partitioning process of HLW, the organic complexing agent will be exposed to -particles emitted by -decay of the actinides. In this study, -radiolysis of TODGA in -dodecane was investigated by the irradiation with helium ion beam accelerated by the AVF cyclotron or the tandem accelerator in the TIARA facility at JAEA Takasaki. It was found that the radiation chemical yield for the degradation of TODGA by helium ion beam irradiation was less than that by -rays irradiation. It was also observed the radiation chemical yield gradually increased with the incident energy of helium ions. These results indicate that the radiolytic degradation of TODGA is reduced by high LET radiations such as -particles. Because the radical cations of -dodecane, which contribute to the charge transfer reaction described above, decrease by recombination in track.
Kondo, Takafumi*; Asano, Akira*; Yang, J.*; Norizawa, Kimihiro*; Takahashi, Kenji*; Taguchi, Mitsumasa; Nagaishi, Ryuji; Kato, Ryuji*; Yoshida, Yoichi*
Radiation Physics and Chemistry, 78(12), p.1157 - 1160, 2009/12
Times Cited Count：28 Percentile：85.84(Chemistry, Physical)Spectrum and kinetic behavior of solvated electrons (e
) in alkyl ammonium ionic liquids (ILs), 
DEMMA-TFSI, DEMMA-BF4, TMPA-TFSI, PP13-TFSI, P13-TFSI and P14-TFSI were investigated by pulse radiolysis method. The e in the ILs have same absorption peak at 1100 nm with a molar absorption coefficient of 1.5-2.3
10
dm
mol
cm. The reaction rate constant of e with Pyrene (Py) was 1.5-3.510
dmmols. These values were about one order of magnitude higher than that of diffusion controlled limit, which was calculated from measured viscosity. The dry electron (e
) reacts with Py, and its rate constant in DEMMA-TFSI was 7.910
dmmols, three orders of magnitude higher than that of the e reactions.
Maruyama, Ryuji; Hino, Masahiro*; Hayashida, Hirotoshi; Kitaguchi, Masaaki*; Achiwa, Norio*; Yamazaki, Dai; Ebisawa, Toru*; Soyama, Kazuhiko
Physica B; Condensed Matter, 404(17), p.2594 - 2599, 2009/09
Times Cited Count：3 Percentile：16.82(Physics, Condensed Matter)Neutron resonance spin echo (NRSE) is one of the most useful techniques for quasi-elastic scattering with high energy resolution. The path length variation due to the beam divergence has to be corrected in high resolution NRSE measurement because it gives the limit in the energy resolution. A neutron focusing technique using neutron supermirrors is effective to overcome this problem. When a cylindrical shaped neutron supermirror placed in the center of the flight path with a pair of RSFs has the object and the image plane corresponding to the each coil plane of the first and the second RSF, the path length difference can be corrected for the neutron beam with large divergent angle, which leads to the realization of high intensity as well as high resolution in NRSE measurement. In this study, the correction method of the beam divergence with a cylindrical shaped supermirror and its experimental results are discussed.
-ray irradiation of organic extractants for the separation of minor actinides by the tandem acceleratorSugo, Yumi; Akamatsu, Ken; Hase, Yoshihiro; Taguchi, Mitsumasa; Sasaki, Yuji; Hirota, Koichi; Kimura, Takaumi
JAEA-Conf 2008-012, p.127 - 129, 2009/03
no abstracts in English
