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Journal Articles

Defect analysis of matrix damage in reactor pressure vessel steel using WB-STEM

Yoshida, Kenta*; Toyama, Takeshi*; Inoue, Koji*; Nagai, Yasuyoshi*; Shimodaira, Masaki

Materia, 62(3), p.154 - 158, 2023/03

no abstracts in English

Journal Articles

Investigation of Cu diffusivity in Fe by a combination of atom probe experiments and kinetic Monte Carlo simulation

Zhao, C.*; Suzudo, Tomoaki; Toyama, Takeshi*; Nishitani, Shigeto*; Inoue, Koji*; Nagai, Yasuyoshi*

Materials Transactions, 62(7), p.929 - 934, 2021/07

 Times Cited Count:2 Percentile:26.82(Materials Science, Multidisciplinary)

We succeeded in measuring the diffusion coefficient of Cu in Fe in a low temperature range that had not been measured so far. Since the diffusion couple, which is a general method for measuring the diffusion coefficient, can be applied only at high temperature, atom probe tomography and Cu precipitation rate theory were used in this study. The estimated diffusion coefficient was found to be more reliable than that obtained in previous studies. Therefore, it is considered that the estimation by the atom probe provided higher accuracy. Furthermore, the kinetic Monte Carlo simulation revealed that the diffusion coefficient estimated by this method tends to be slightly overestimated as the temperature decreases.

Journal Articles

Dating of buried wood logs and fragments for high resolution reconstruction of landslide histories; Case studies in the Japanese Alps region in the historical times

Yamada, Ryuji*; Kimura, Takashi*; Kariya, Yoshihiko*; Sano, Masaki*; Tsushima, Akane*; Li, Z.*; Nakatsuka, Takeshi*; Kokubu, Yoko; Inoue, Kimio*

Sabo Gakkai-Shi, 73(5), p.3 - 14, 2021/01

We discuss the applicability of dating methods for determining landslide chronologies in relation to the type of samples and the sampling location. Case studies are carried out with fossil wood samples buried in the colluvial soil of large-scale landslides occurred in two areas of the Japanese Alps region. Ages are determined by accelerator mass spectrometry radiocarbon dating and dendrochronological analysis using the oxygen isotope composition of tree ring cellulose. Most of ages for Dondokosawa rock avalanche are concordant with the period of AD 887 Ninna (Goki-Shichido) earthquake. Ages for Ohtsukigawa debris avalanche are not concentrated in a specific period. In order to obtain accurate age of large-scale landslide, utilizing buried large diameter tree trunk or branches with the good preservation condition has a lot of advantages because it allows us to compare the landslide chronology with historical records of heavy rainfall and large earthquakes.

Journal Articles

${it In situ}$ WB-STEM observation of dislocation loop behavior in reactor pressure vessel steel during post-irradiation annealing

Du, Y.*; Yoshida, Kenta*; Shimada, Yusuke*; Toyama, Takeshi*; Inoue, Koji*; Arakawa, Kazuto*; Suzudo, Tomoaki; Milan, K. J.*; Gerard, R.*; Onuki, Somei*; et al.

Materialia, 12, p.100778_1 - 100778_10, 2020/08

In order to ensure the integrity of the reactor pressure vessel in the long term, it is necessary to understand the effects of irradiation on the materials. In this study, irradiation-induced dislocation loops were observed in neutron-irradiated reactor pressure vessel specimens during annealing using our newly developed WB-STEM. It was confirmed that the proportion of $$<100>$$ loops increased with increasing annealing temperature. We also succeeded in observing the phenomenon that two $$frac{1}{2}$$$$<111>$$ loops collide into a $$<100>$$ loop. Moreover, a phenomenon in which dislocation loops decorate dislocations was also observed, and the mechanism was successfully explained by molecular dynamics simulation.

Journal Articles

Thermal behavior, structure, dynamic properties of aqueous glycine solutions confined in mesoporous silica MCM-41 investigated by X-ray diffraction and quasi-elastic neutron scattering

Yoshida, Koji*; Inoue, Takuya*; Torigoe, Motokatsu*; Yamada, Takeshi*; Shibata, Kaoru; Yamaguchi, Toshio*

Journal of Chemical Physics, 149(12), p.124502_1 - 124502_10, 2018/09

 Times Cited Count:3 Percentile:12.78(Chemistry, Physical)

Differential scanning calorimetry, X-ray diffraction, and quasi-elastic neutron scattering (QENS) measurements of aqueous glycine solutions confined in mesoporous silica (MCM-41) were performed at different glycine concentrations, pH, and loading ratio (= mass of glycine solution / mass of dry MCM-41) in the temperature range from 305 to 180 K to discuss the confinement effect on the thermal behavior, the structure, and the dynamic properties of the solutions.

Journal Articles

Experimental investigation of the glass transition of polystyrene thin films in a broad frequency range

Inoue, Rintaro*; Kanaya, Toshiji*; Yamada, Takeshi*; Shibata, Kaoru; Fukao, Koji*

Physical Review E, 97(1), p.012501_1 - 012501_6, 2018/01

 Times Cited Count:9 Percentile:63.13(Physics, Fluids & Plasmas)

In this study, we investigate the $$alpha$$ process of a polystyrene thin film using inelastic neutron scattering (INS), dielectric relaxation spectroscopy (DRS), and thermal expansion spectroscopy (TES). The DRS and TES measurements exhibited a decrease in glass transition temperature ($$T_{rm g}$$) with film thickness. On the other hand, an increase in $$T_{rm g}$$ was observed in INS studies. In order to interpret this contradiction, we investigated the temperature dependence of the peak frequency ($$f_{rm m}$$) of the $$alpha$$ process probed by DRS and TES. The experiments revealed an increase in the peak frequency ($$f_{rm m}$$) with decreasing film thickness in the frequency region. This observation is consistent with the observed decrease in $$T_{rm g}$$ with thickness. The discrepancy between INS and DRS or TES descriptions of the $$alpha$$ process is likely to be attributed to a decrease in the apparent activation energy with film thickness and reduced mobility, due to the impenetrable wall effect.

Journal Articles

Predoping effects of boron and phosphorous on arsenic diffusion along grain boundaries in polycrystalline silicon investigated by atom probe tomography

Takamizawa, Hisashi; Shimizu, Yasuo*; Inoue, Koji*; Nozawa, Yasuko*; Toyama, Takeshi*; Yano, Fumiko*; Inoue, Masao*; Nishida, Akio*; Nagai, Yasuyoshi*

Applied Physics Express, 9(10), p.106601_1 - 106601_4, 2016/10

 Times Cited Count:0 Percentile:0(Physics, Applied)

Journal Articles

Design and performance of high-pressure PLANET beamline at pulsed neutron source at J-PARC

Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Komatsu, Kazuki*; Yamada, Akihiro*; Inamura, Yasuhiro; Nakatani, Takeshi; Seto, Yusuke*; Nagai, Takaya*; Utsumi, Wataru; et al.

Nuclear Instruments and Methods in Physics Research A, 780, p.55 - 67, 2015/04

 Times Cited Count:68 Percentile:98.97(Instruments & Instrumentation)

PLANET is a time-of-flight (ToF) neutron beamline dedicated to high-pressure and high-temperature experiments. The large six-axis multi-anvil high-pressure press designed for ToF neutron diffraction experiments enables routine data collection at high pressures and high temperatures up to 10 GPa and 2000 K, respectively. To obtain clean data, the beamline is equipped with the incident slits and receiving collimators to eliminate parasitic scattering from the high-pressure cell assembly. The high performance of the diffractometer for the resolution ($$Delta$$ $$d$$/$$d$$ $$sim$$ 0.6%) and the accessible $$d$$-spacing range (0.2-8.4 ${AA}$) together with low-parasitic scattering characteristics enables precise structure determination of crystals and liquids under high pressure and temperature conditions.

Journal Articles

Investigating 3S synergies to support infrastructure development and risk-informed methodologies for 3S by design

Suzuki, Mitsutoshi; Izumi, Yoshinori; Kimoto, Toru; Naoi, Yosuke; Inoue, Takeshi; Hoffheins, B.

IAEA-CN-184/64 (Internet), 8 Pages, 2010/11

In support of the 3S initiative, Japan Atomic Energy Agency (JAEA) has been conducting detailed analyses of the R&D programs and cultures of each of the S areas to identify overlaps where synergism and efficiencies might be realized, to determine where there are gaps in the development of a mature 3S culture, and to coordinate efforts with other Japanese and international organizations. Lessons learned in these activities can be applied to developing more efficient and effective 3S infrastructures for incorporating into Safeguards by Design methodologies. In this presentation, a risk-informed approach regarding integration of 3S will be introduced. An initial examination of incident probability and postulated consequence analyses, which are tools familiar to the nuclear safety culture, will be applied to predict and evaluate inherent uncertainties of proliferation and security risks.

Journal Articles

Effects of aluminum on high-temperature strength of 9Cr-ODS steel

Otsuka, Satoshi; Kaito, Takeji; Inoue, Masaki; Asayama, Tai; Kim, S.-W.; Ukai, Shigeharu*; Narita, Takeshi*; Sakasegawa, Hideo*

Journal of Nuclear Materials, 386-388, p.479 - 482, 2009/04

 Times Cited Count:18 Percentile:76.39(Materials Science, Multidisciplinary)

This paper discusses the effects of small portion of Al contamination ($$<$$0.1wt%) on the high-temperature strength and microstructure of 9Cr-ODS steel. Increasing Al concentration is shown to provide small reduction of ultimate tensile strength as well as 0.2% proof stress at 973 K and 1073 K accompanied by reduction of elongated grains i.e. residual-$$alpha$$ ferrite acting as reinforcement phase. Addition of Al appears to increase the proportion of ferrite phase, which is contrary to general behavior in conventional steels. This unique behavior could be peculiar to the non-equilibrium materials such as mechanically-alloyed alloy. Computer simulation on phase transformation suggests that the fine oxide dispersion in the elongated ferrite could be attributable to the preferential partitioning of Ti and W in ferrite than in austenite at hot-extrusion process at 1423 K.

Journal Articles

The Change of water quality during rain event at Ijira river

Takahashi, Shinya*; Inoue, Takanobu*; Tsushima, Koji*; Sakioka, Masamichi*; Matsunaga, Takeshi

Kankyo Kogaku Kenkyu Rombunshu, 46, p.565 - 572, 2009/00

This study analyzed the changes of water quality during rain events at Ijira river, a mountain stream in Gifu Prefecture, by measured the major ion concentration, pH, electric conductivity, discharge, and hydrograph separation using deuterium isotope ratio of the water. During rain events, where the discharge is increase, almost all of the major ion concentration, pH and electric conductivity were decreased. We also found that the correlation of the changes of pH and the changes of electric conductivity with precipitation were negative. The result of hydrograph separation shows that the ratio of surface runoff for discharge is increased with an increased of the precipitation, and also increased in the high precipitation. It was shown that the major factor of the changes of water quality in this study site is the contribution of surface runoff.

Journal Articles

Status of reduced enrichment program for research reactors in Japan

Oba, Toshinobu; Inoue, Takeshi; Unesaki, Hironobu*

Proceedings of International Meeting on Reduced Enrichment for Research and Test Reactors 2008 (RERTR 2008) (Internet), 10 Pages, 2008/10

The current status of research and test reactors relevant to RERTR program is described. The reduced enrichment programs for the JRR-3, JRR-4 and JMTR of Japan Atomic Energy Agency (JAEA) were completed by 1999. The core of JRR-3 was converted from aluminide (UAl$$_{x}$$-Al) to silicide (U$$_{3}$$Si$$_{2}$$-Al) in order to reduce the amount of spent fuel. The JRR-3 has been well operated with LEU fuel since 1990 and reached 55,400 MWD in December 2007 at the last operation cycle. Operation with 10 cycles (26 days/cycle) is scheduled for one year from July 2008 to July 2009. The JRR-4 is under shut down condition to replace reflector elements with new ones. It will restart in July 2009. The JMTR is under refurbishment of irradiation facilities. Kyoto University Research Reactor (KUR) has terminated its operation with HEU on February 2006. Shipment of all HEU spent fuel elements to the United States has been successfully completed. The full core conversion of KUR to LEU fuel, including fuel fabrication, is currently under progress and the reactor restart using LEU core is expected to be achieved in May 2009.

JAEA Reports

Verification of distributed rainfall-runoff model using a hydrogen isotopic ratio, and analysis of nitrate nitrogen transport to a stream (Joint research)

Tsuzuki, Katsunori; Matsunaga, Takeshi; Inoue, Takanobu*

JAEA-Research 2008-008, 31 Pages, 2008/03

JAEA-Research-2008-008.pdf:3.68MB

The discharge of nitrate nitrogen from a forested catchment was analyzed using a distributed rainfall-runoff model. Observation in rainfall events were carried out in November, 2006 in the Ijira River. The distributed rainfall-runoff model carried out runoff simulation of ground water and rain water at the catchment. The model was verified by observed flow rate, and the hydrogen isotopic ratio of rain water and river water. The nitrate ion concentration in river water was shown as a function of the residence time of discharge water in the catchment calculated by the model. As a result, it was estimated that the nitric-acid ion in the river water was transported by the lateral flow of the rain water at the subsurface and the up-flow of ground water. Moreover, it was estimated that the residence time of the soil moisture influenced the discharge of nitrate nitrogen. This study was suggested that dynamic behavior of water in catchment was important when considering the balance of nitrate nitrogen in catchment.

JAEA Reports

Analytical work at NUCEF in FY 2006

Sakazume, Yoshinori; Aoki, Hiromichi; Haga, Takahisa; Fukaya, Hiroyuki; Sonoda, Takashi; Shimizu, Kaori; Niitsuma, Yasushi*; Ito, Mitsuo; Inoue, Takeshi

JAEA-Technology 2007-069, 44 Pages, 2008/02

JAEA-Technology-2007-069.pdf:4.55MB

Analysis of the uranyl nitrate solution fuel is carried out at the analytical laboratory of NUCEF (Nuclear Fuel Cycle Engineering Research Facility), which provides essential data for operation of STACY (Static Experiment Critical Facility), TRACY (Transient Experiment Critical Facility) and the fuel treatment system. Analyzed in FY 2006 were uranyl nitrate solution fuel samples taken before and after experiments of STACY and TRACY, samples for the preparation of uranyl nitrate solution fuel, and samples for nuclear material accountancy purpose. The total number of the samples analyzed in FY 2006 was 254. This report summarizes work related to the analysis and management of the analytical laboratory in the FY 2006.

JAEA Reports

Analytical work at NUCEF in FY 2005

Fukaya, Hiroyuki; Aoki, Hiromichi; Haga, Takahisa; Nishizawa, Hidetoshi; Sonoda, Takashi; Sakazume, Yoshinori; Shimizu, Kaori; Niitsuma, Yasushi*; Shirahashi, Koichi; Inoue, Takeshi

JAEA-Technology 2007-005, 27 Pages, 2007/03

JAEA-Technology-2007-005.pdf:1.97MB

Analysis of the uranyl nitrate solution fuel is carried out at the analytical laboratory of NUCEF (Nuclear Fuel Cycle Engineering Research Facility), which provides essential data for operation of STACY (Static Experiment Critical Facility), TRACY (Transient Experiment Critical Facility) and the fuel treatment system. Analyzed in FY 2005 were uranyl nitrate solution fuel samples taken before and after experiments of STACY and TRACY, samples for the preparation of uranyl nitrate solution fuel, and samples for nuclear material accountancy purpose. Also analyzed were the samples from raffinate treatment and its preliminary tests. The raffinate was generated, since FY 2000, during preliminary experiments on U/Pu extraction-pulification to fix the operation condition to prepare plutonium solution fuel to be used for criticality experiments at STACY. This report summarizes work related to the analysis and management of the analytical laboratory in the FY 2005.

Journal Articles

Stream discharge of metals and rare earth elements in rainfall events in a forested catchment

Matsunaga, Takeshi; Tsuzuki, Katsunori; Yanase, Nobuyuki; Hanzawa, Yukiko; Naganawa, Hirochika; Inoue, Takanobu*; Yamada, Toshiro*; Miyata, Akifumi*

Proceedings of International Symposium on Environmental Modeling and Radioecology, p.243 - 246, 2007/03

The aim of this work is to obtain a fundamental scheme of stream discharge of inorganic toxic materials derived from Characteristics of the stream discharge of metallic elements were investigated in two forested catchments in the Oda River and the Ijira River watersheds. Precipitations, stream water and soil water samples were collected in raining events and were analyzed for inorganic elements, dissolved organic carbon and isotopic abundance of deuterium. Results revealed an accelerated discharge of specific metals of Cu, Sb and Cr and all the studied REE in dissolved form. This feature was commonly found in the two catchments. The specific metals are strongly suspected to be of anthropogenic origin. An analysis of hydrological discharge, using chemical and isotopic tracers, suggested that the increased discharge of the metals originate from their deposits on the ground surface and/or instantaneous resuspension of stream sediment. Contrary, REE discharge was tightly coupled with that of dissolved humic substances.

Journal Articles

Status of reduced enrichment program for research reactors in Japan

Unesaki, Hironobu*; Ota, Kazunori; Inoue, Takeshi

Proceedings of International Meeting on Reduced Enrichment for Research and Test Reactors 2007 (RERTR 2007) (Internet), 11 Pages, 2007/00

The status of reduced enrichment program for research reactors in Japan will be reviewed. Among the fourteen research reactors and critical assemblies in operation in Japan, those concerned with the RERTR program are the JRR-3, JRR-4 and JMTR of Japan Atomic Energy Agency (JAEA) and KUR of Kyoto University Research Reactor Institute (KURRI). Reduced enrichment programs for the JRR-3, JRR-4 and JMTR of JAEA has been completed by 1999, and the reactors are being satisfactory operated using LEU fuels. In KURRI, the KUR has terminated its operation with HEU on February 2006. Licensing for the full core conversion of KUR to LEU fuel is under progress and the core conversion to LEU is expected to be completed in 2008.

Journal Articles

Si substrate suitable for radiation-resistant space solar cells

Matsuura, Hideharu*; Iwata, Hiroshi*; Kagamihara, So*; Ishihara, Ryohei*; Yoneda, Masahiko*; Imai, Hideaki*; Kikuta, Masanori*; Inoue, Yuki*; Hisamatsu, Tadashi*; Kawakita, Shiro*; et al.

Japanese Journal of Applied Physics, Part 1, 45(4A), p.2648 - 2655, 2006/04

 Times Cited Count:15 Percentile:49.35(Physics, Applied)

no abstracts in English

JAEA Reports

Annual report on analytical works at NUCEF in FY 2004

Nishizawa, Hidetoshi; Fukaya, Hiroyuki; Sonoda, Takashi; Sakazume, Yoshinori; Shimizu, Kaori; Haga, Takahisa; Sakai, Yutaka*; Akutsu, Hideyuki*; Niitsuma, Yasushi; Inoue, Takeshi; et al.

JAEA-Technology 2006-007, 24 Pages, 2006/03

JAEA-Technology-2006-007.pdf:1.81MB

Analysis of the uranyl nitrate solution fuel is carried out at the analytical laboratory of NUCEF(Nuclear Fuel Cycle Engineering Research Facility), which provides essential data for operation of STACY(Static Experiment Critical Facility), TRACY(Transient Experiment Critical Facility)and the fuel treatment system. Analyzed in FY 2004 were uranyl nitrate solution fuel samples taker before and after experiments of STACY and TRACY, samples for the preparation of uranyl nitrate solution fuel, and samples for nuclear material accountancy purpose. Also analyzed were the samples from raffinate treatment and its preliminary tests. The raffinate was generated, since FY 2000, during preliminary experiments on U/Pu extraction-pulification to fix the operation condition to prepare plutonium solution fuel to be used for criticality experiments at STACY. The total number of the samples analyzed in FY 2004 was 160. This report summarizes works related to the analysis and management of the analytical laboratory in the FY 2004.

Journal Articles

Sensor noise caused by vibrations of flaw detection probe generated in helical heating tubes in a fast breeder reactor and its countermeasures, 2; Numerical simulations of probe vibration

Inoue, Takumi*; Sueoka, Atsuo*; Maehara, Takeshi*; Nakano, Hiroshi*; Kanemoto, Hiroyuki*; Murakami, Yukitaka*

Nihon Kikai Gakkai Rombunshu, C, 72(714), p.380 - 387, 2006/02

None

47 (Records 1-20 displayed on this page)