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JAEA Reports

Report on decontamination pilot projects to establish guidelines for environmental remediation of residential areas contaminated with radioactive materials discharged from the Fukushima Daiichi Nuclear Power Station Accident

Kihara, Shinji; Amazawa, Hiroya; Sakai, Akihiro; Nakata, Hisakazu; Kugo, Teruhiko; Matsuda, Norihiro; Oizumi, Akito; Sasamoto, Hiroshi; Mitsui, Seiichiro; Miyahara, Kaname

JAEA-Research 2013-033, 320 Pages, 2014/07

JAEA-Research-2013-033.pdf:119.17MB

JAEA performed decontamination experiments at two test sites that combined a range of buildings and different types of land use, located in Date and Minami Soma municipalities as field pilot projects in order to accumulate knowledge and data for full-scale decontamination activities performed by local governments. In the pilot projects, we established its plan using practical decontamination methods that can be easily implemented, according to decontamination targets (e.g., forests, agricultural land, residential house and roads) at each site. As a result of the decontamination, the average air dose rates were reduced to approximately one half of the values before decontamination.

Journal Articles

Valence state in Ce-based heavy fermion compounds at high magnetic fields

Matsuda, Yasuhiro*; Her, J.-L.*; Michimura, Shinji*; Inami, Toshiya; Ebihara, Takao*; Amitsuka, Hiroshi*

JPS Conference Proceedings (Internet), 3, p.011044_1 - 011044_6, 2014/06

Synchrotron X-ray absorption spectroscopy of CeRh$$_2$$Si$$_2$$ has been performed in pulsed high magnetic fields of up to 32 T. The Ce valence is slightly larger than 3+ at 5 K and decreases with increasing magnetic above 20 T. The field-induced valence change seems to correspond to the metamagnetic transition in the magnetization process. This phenomena is similar to our previous result on CeRu$$_2$$Si$$_2$$ and seems to be common in Ce-based heavy fermion compounds.

Journal Articles

Magnetic-field-induced charge order in the filled skutterudite SmRu$$_{4}$$P$$_{12}$$; Evidence from resonant and nonresonant X-ray diffraction

Matsumura, Takeshi*; Michimura, Shinji*; Inami, Toshiya; Hayashi, Yuya*; Fushiya, Kengo*; Matsuda, Tatsuma*; Higashinaka, Ryuji*; Aoki, Yuji*; Sugawara, Hitoshi*

Physical Review B, 89(16), p.161116_1 - 161116_5, 2014/04

 Times Cited Count:15 Percentile:54.61(Materials Science, Multidisciplinary)

The antiferromagnetic ordered phase below $$T_{rm MI}$$ = 16.5 K and the unresolved intermediate phase between $$T_{rm MI}$$ and $$T^*$$ (= 14 K) in SmRu$$_4$$P$$_{12}$$ have been studied by resonant and nonresonant X-ray diffraction. In the intermediate phase, nonresonant Thomson scattering with $$q$$ = (1,0,0) is induced by applying a magnetic field. This phenomena is caused by atomic displacements reflecting the charge order in the $$p$$ band, as predicted theoretically. Simultaneously, the antiferromagnetic moment of Sm is enhanced along the field direction, which is considered to reflect the staggered ordering of the $$Gamma_7$$ - $$Gamma_8$$ crystal-field states. The present results show that the orbital-dependent $$p$$ - $$f$$ hybridization in association with the nesting instability in the $$p$$ band gives rise to the unconventional charge order similarly with PrRu$$_4$$P$$_{12}$$ and PrFe$$_4$$P$$_{12}$$.

Journal Articles

Temperature and magnetic field dependent Yb valence in YbRh$$_2$$Si$$_2$$ observed by X-ray absorption spectroscopy

Nakai, Hirohito*; Ebihara, Takao*; Tsutsui, Satoshi*; Mizumaki, Masaichiro*; Kawamura, Naomi*; Michimura, Shinji*; Inami, Toshiya; Nakamura, Toshiyuki*; Kondo, Akihiro*; Kindo, Koichi*; et al.

Journal of the Physical Society of Japan, 82(12), p.124712_1 - 124712_5, 2013/12

 Times Cited Count:8 Percentile:50.87(Physics, Multidisciplinary)

The temperature and magnetic field dependences of Yb valence were observed in the heavy fermion compoundYbRh$$_2$$Si$$_2$$ by X-ray absorption spectroscopy. The measurements revealed that the Yb valence decreases with decreasing temperature in the range from 200 to 2 K and increases with increasing magnetic field in the range from 0 to 33 T without showing an abrupt change in the Yb valence. The Yb valence is in the range from 2.92 to 2.96 depending on temperature and magnetic field. With respect to the valence being 2.92 at 0 T and 2.93 at 33 T in 2 K, YbRh$$_2$$Si$$_2$$ is a valence fluctuation compound and does not reach the integer trivalent state at high magnetic field. These results endorse the conventional knowledge that the valence of Yb is very close to the integer value of 3+, decreases with decreasing temperature, and becomes closer to 3+ with increasing magnetic field.

Journal Articles

Synchrotron X-ray spectroscopy study on the valence state in $$alpha$$- and $$beta$$-TbAlB$$_4$$ at low temperature and high magnetic fields

Matsuda, Yasuhiro*; Nakamura, Toshiyuki*; Kuga, Kentaro*; Nakatsuji, Satoru*; Michimura, Shinji*; Inami, Toshiya; Kawamura, Naomi*; Mizumaki, Masaichiro*

Journal of the Korean Physical Society, 62(12), p.1778 - 1781, 2013/06

 Times Cited Count:10 Percentile:56.13(Physics, Multidisciplinary)

The valence state of Yb ions in $$alpha$$- and $$beta$$-YbAlB$$_4$$ has been investigated by X-ray absorption and emission spectroscopy at temperatures from 2 to 280 K. It is found that the valence gradually increases with increasing temperature toward 3+ and that the characteristic temperature of the valence fluctuations is about 290 K. We also observe a small increase in the Yb valence ($$sim$$ 0.002) in $$beta$$-YbAlB$$_4$$ by a magnetic field of 32 T at 40 K.

Journal Articles

High-magnetic-field X-ray absorption and magnetic circular dichroism spectroscopy in the mixed-valent compound YbAgCu$$_4$$

Nakamura, Toshiyuki*; Matsuda, Yasuhiro*; Her, J.-L.*; Kindo, Koichi*; Michimura, Shinji*; Inami, Toshiya; Mizumaki, Masaichiro*; Kawamura, Naomi*; Suzuki, Motohiro*; Chen, B.*; et al.

Journal of the Physical Society of Japan, 81(11), p.114702_1 - 114702_11, 2012/11

 Times Cited Count:11 Percentile:57.68(Physics, Multidisciplinary)

The X-ray absorption and magnetic circular dichroism (MCD) spectra at the Yb L$$_3$$ edge were measured in the mixed-valent heavy fermion compound YbAgCu$$_4$$ at high magnetic fields and low temperatures. The magnetic-field-temperature (H-T) phase boundary determined by the valence state is in very good agreement with that determined by the magnetization. It is clearly found that the metamagnetism of this compound is due to the field induced valence transition. A distinctive positive peak of the XMCD spectra appears in the vicinity of the white line of the absorption due to Yb$$^{3+}$$ state, while no feature is observed in the XMCD spectra corresponding to the Yb$$^{2+}$$ state. A small negative XMCD peak was observed at a lower energy and was attributed to the quadrupole trasition from theoretical calcuration, which explains its peculicar magnetic field dependence.

Journal Articles

Suppression of $$f$$-electron itinerancy in CeRu$$_2$$Si$$_2$$ by a strong magnetic field

Matsuda, Yasuhiro*; Nakamura, Toshiyuki*; Her, J. L.*; Michimura, Shinji*; Inami, Toshiya; Kindo, Koichi*; Ebihara, Takao*

Physical Review B, 86(4), p.041109_1 - 041109_4, 2012/07

 Times Cited Count:9 Percentile:38.45(Materials Science, Multidisciplinary)

The valence state of Ce in a typical heavy fermion compound CeRu$$_2$$Si$$_2$$ has been investigated by synchrotron X-ray absorption spectroscopy at 1.8 K in high magnetic fields of up to 40T. The valence was slightly larger than for the pure trivalent state, as expected in heavy fermion compounds, and it decreased toward the trivalent state as the magnetic field was increased. The field-induced valence reduction indicates that the itinerant character of the 4$$f$$ electrons in CeRu$$_2$$Si$$_2$$ was suppressed by a strong magnetic field. The suppression was gradual and showed a characteristic magnetic field dependence, which reflects the metamagnetism around $$H_{rm m}$$ $$sim$$ 8T.

Journal Articles

Valence fluctuation in YbAgCu$$_4$$ at high Magnetic fields

Matsuda, Yasuhiro*; Nakamura, Toshiyuki*; Her, J.-L.*; Kindo, Koichi*; Michimura, Shinji*; Inami, Toshiya; Mizumaki, Masaichiro*; Kawamura, Naomi*; Suzuki, Motohiro*; Chen, B.*; et al.

Journal of the Physical Society of Japan, 81(1), p.015002_1 - 015002_2, 2012/01

 Times Cited Count:11 Percentile:57.68(Physics, Multidisciplinary)

The valence change of Yb ion in YbAgCu$$_4$$ was measured by means of X-ray absorption spectroscopy under high magnetic fields up to 35T. The valence state of Yb in YbAgCu$$_4$$ at 4.8K significantly increases at the metamagnetic transition. The saturation value of $$v$$ at 55T is evaluated as 2.97 using the relation $$Delta M/Delta v$$ at 35T. This value is in good agreement with $$v$$ for the related compound YbInCu$$_4$$ at high temperatures and the Yb valence in the localized high-field phase. We conclude that the metamagnetic transition in YbAgCu$$_4$$ arises from the valence transition, as theoretically predicted.

Journal Articles

Orbital magnetism in Cd$$_2$$Os$$_2$$O$$_7$$ studied by X-ray magnetic circular dichroism

Matsuda, Yasuhiro*; Her, J.-L.*; Michimura, Shinji*; Inami, Toshiya; Suzuki, Motohiro*; Kawamura, Naomi*; Mizumaki, Masaichiro*; Kindo, Koichi*; Yamaura, Junichi*; Hiroi, Zenji*

Physical Review B, 84(17), p.174431_1 - 174431_5, 2011/11

 Times Cited Count:25 Percentile:69.69(Materials Science, Multidisciplinary)

X-ray magnetic circular dichroism (XMCD) at the $$L$$$$_{2,3}$$-edge of Os has been investigated in the antiferromagneticphase of Cd$$_2$$Os$$_2$$O$$_7$$, which exhibits a metal-insulator transition around 227 K. According to the sum rule, the XMCD spectra at 10 and 37 T clearly show that the ratio between the orbital magnetic moment ($$m_{rm L}$$) and spinmagnetic moment ($$m_{rm S}$$) is $$m_{rm L}/m_{rm S} = 0.16 pm 0.02$$, and that $$m_{rm L}$$ and $$m_{rm S}$$ are coupled in parallel ($$m_{rm L}parallel m_{rm S}$$). These phenomena are unusual in that the expected ground state of Os$$^{5+}$$ (5$$d^3$$) is an orbital singlet in a cubic crystal field, and $$m_{rm L}$$and $$m_{rm S}$$ should be antiparallel for a less than half-filled system in accordance with Hund's third rule. It is likely that the spin-orbit coupling is important for explaining the observed orbital magnetism.

Journal Articles

Observation of two charge ordering transitions in the valence-fluctuating EuPtP by resonant X-ray diffraction

Inami, Toshiya; Michimura, Shinji; Mitsuda, Akihiro*; Wada, Hirofumi*

Physical Review B, 82(19), p.195133_1 - 195133_5, 2010/11

 Times Cited Count:11 Percentile:46.2(Materials Science, Multidisciplinary)

Two first-order phase transitions of the valence-fluctuating compound EuPtP at $$T_1$$=246 K and $$T_2$$=200 K were examined by means of resonant X-ray diffraction at the Eu $$L_3$$ absorption edge. Although previous M$"o$ssbauer spectroscopy and preliminary X-ray diffraction experiments have suggested charge ordered states, characteristic energy spectra of the 111 and 11$$frac{2}{3}$$ reflections observed in the present experiment unambiguously indicated that twofold and threefold superstructures of Eu valence exist below $$T_2$$ and between $$T_1$$ and $$T_2$$, respectively. We also propose a mechanism to explain the charge ordering in EuPtP based on a charge-lattice coupling that alters a Coulomb repulsion.

JAEA Reports

Studies on grouting performance in Mizunami Underground Research Laboratory (Contract research)

Kawamura, Hideki*; Ando, Kenichi*; Noda, Masaru*; Tanaka, Tatsuya*; Matsuda, Takeshi*; Fujii, Haruhiko*; Hashimoto, Shuji*; Ueda, Tadashi*; Matsui, Hiroya; Takeuchi, Shinji; et al.

JAEA-Technology 2009-081, 182 Pages, 2010/03

JAEA-Technology-2009-081.pdf:28.89MB

Grouting has practical importance for the reduction of groundwater inflow into excavations during construction of underground facilities. Considering the performance assessment of a radioactive waste repository, the performance of the engineered barrier system could be adversely affected by a high pH plume generated from grout. Therefore, a quantitative estimation of the effectiveness of grouting and grout material is essential. This study has been performed in the Mizunami URL being excavated in crystalline rock as a part of the Project for Grouting Technology Development for the Radioactive Waste Repository funded by METI, Japan. The aims were to evaluate the applicability of existing grouting technology and to develop methodology to determine the distribution of grout and change in hydraulic properties of the grouted rock volume. The target rock is the volume of rock around a planned refuge niche where the pre-excavation grouting was performed at 200-m depth from ground surface. After excavation of the refuge niche, ten boreholes were drilled and different kinds of investigations were carried out during and after drilling. The results were integrated and groundwater flow analysis of pre and post excavation grouting conditions were carried out to estimate quantitatively the effect of pre-excavation grouting. The results suggest that current pre-excavation grouting technology is effective for reduction of groundwater inflow into excavations and that hydraulic conductivity of the surrounding rock can be reduced by more than one order of magnitude.

Journal Articles

JT-60SA project for JA-EU broader approach satellite tokamak and national centralized tokamak

Kikuchi, Mitsuru; Matsuda, Shinzaburo; Yoshida, Naoaki*; Takase, Yuichi*; Miura, Yukitoshi; Fujita, Takaaki; Matsukawa, Makoto; Tamai, Hiroshi; Sakurai, Shinji; Ikeda, Yoshitaka; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 82(8), p.455 - 469, 2006/08

no abstracts in English

Journal Articles

Critical $$beta$$ analyses with ferromagnetic and plasma rotation effects and wall geometry for a high $$beta$$ steady state tokamak

Kurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi*; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.

Nuclear Fusion, 46(2), p.383 - 390, 2006/02

 Times Cited Count:9 Percentile:31.27(Physics, Fluids & Plasmas)

It is shown that critical beta is decreased by ferromagnetic effect by about 8% for $$mu$$/$$mu$$$$_{0}$$$$sim$$2, $$mu$$ and $$mu$$$$_{0}$$ denoting the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window for resistive wall mode opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.

Journal Articles

Critical $$beta$$ analyses with ferromagnetic and plasma rotation effects and wall geometry for a high $$beta$$ steady state tokamak

Kurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.

IAEA-CN-116/FT/P7-7 (CD-ROM), 8 Pages, 2004/11

The critical beta is shown to be decreased by ferromagnetic effect by about 8 % for m/m0$$sim$$2, m and m0 denote the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.

Journal Articles

The Structures of alkylimidazolium fluorohydrogenate molten salts studied by high-energy X-ray diffraction

Hagiwara, Rika*; Matsumoto, Kazuhiko*; Tsuda, Tetsuya*; Ito, Yasuhiko*; Kohara, Shinji*; Suzuya, Kentaro; Matsumoto, Hajime*; Miyazaki, Yoshinori*

Journal of Non-Crystalline Solids, 312-314, p.414 - 418, 2002/10

 Times Cited Count:32 Percentile:85.86(Materials Science, Ceramics)

The structures of a series of XF$$^{.}$$2.3HF (X= 1-methylimidazolium (MI), 1-ethyl-3-methylimidazolium (EMI), 1-butyl-3-methylimidazolium (BMI), 1-hexyl-3-methyl-imidazolium (HMI)) room temperature molten salts have been investigated by high-energy synchrotron X-ray diffraction technique. The correlation peaks appeared in the total correlation function are mainly ascribed to intra-molecular correlation of alkylimidazolium cations. However, it is suggested that the peak at around 3.6 $$AA$$ is ascribed not only to intra-molecular but also inter-molecular correlation of the cation. The contribution of the latter is also supported by the first sharp diffraction peak of the total structure factor found at almost the same position as that of a Bragg peak in the simulated X-ray diffraction pattern of solid EMIF$$^{.}$$HF with a layered structure, corresponding to the layer separation of

Journal Articles

Magnetohydrodynamic stability of improved confinement plasmas in JT-60U

Takeji, Satoru; Isayama, Akihiko; Ozeki, Takahisa; Tokuda, Shinji; Ishii, Yasutomo; Oikawa, Toshihiro; Ishida, Shinichi; Kamada, Yutaka; Neyatani, Yuzuru; Yoshino, Ryuji; et al.

Fusion Science and Technology (JT-60 Special Issue), 42(2-3), p.278 - 297, 2002/09

 Times Cited Count:7 Percentile:6.06(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Observation of resistive wall modes in JT-60U

Takeji, Satoru; Tokuda, Shinji; Kurita, Genichi; Suzuki, Takahiro; Isayama, Akihiko; Takechi, Manabu; Oyama, Naoyuki; Fujita, Takaaki; Ide, Shunsuke; Ishida, Shinichi; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 78(5), p.447 - 454, 2002/05

no abstracts in English

Journal Articles

A Highly conductive RTMS; Alkylimidazolium fluorohydrogenates

Hagiwara, Rika*; Matsumoto, Kazuhiko*; Tsuda, Tetsuya*; Kohara, Shinji*; Suzuya, Kentaro; Ito, Yasuhiko*

Proceedings of 6th International Symposium on Molten Salts Chemistry and Technology (MS6), p.136 - 139, 2001/10

no abstracts in English

Journal Articles

Development of trace analytical technology for nuclear materials in the clean laboratory for environmental analysis and research

Usuda, Shigekazu; Watanabe, Kazuo; Sakurai, Satoshi; Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Miyamoto, Yutaka; Yasuda, Kenichiro; Saito, Yoko; Gunji, Katsubumi*; et al.

KEK Proceedings 2001-14, p.88 - 92, 2001/06

no abstracts in English

Journal Articles

Progress of environmental sampling program at Japan Atomic Energy Research Institute

Nishimura, Hideo; Magara, Masaaki; Hanzawa, Yukiko; Esaka, Fumitaka; Takahashi, Tsukasa; Gunji, Katsubumi; Miyamoto, Yutaka; Yasuda, Kenichiro; Tsuruta, Yasuhiro; Tsuda, Shinji; et al.

Heisei 11-Nendo Hosho Sochi Semina Koenroku Tekisuto, p.95 - 107, 2000/01

no abstracts in English

27 (Records 1-20 displayed on this page)