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Journal Articles

Development of a non-destructive depth-selective quantification method for sub-percent carbon contents in steel using negative muon lifetime analysis

Ninomiya, Kazuhiko*; Kubo, Kenya*; Inagaki, Makoto*; Yoshida, Go*; Chiu, I.-H. ; Kudo, Takuto*; Asari, Shunsuke*; Sentoku, Sawako*; Takeshita, Soshi*; Shimomura, Koichiro*; et al.

Scientific Reports (Internet), 14, p.1797_1 - 1797_8, 2024/01

The amount of C in steel, which is critical in determining its properties, is strongly influenced by steel production technology. We propose a novel method of quantifying the bulk C content in steel non-destructively using muons. This revolutionary method may be used not only in the quality control of steel in production, but also in analyzing precious steel archaeological artifacts. A negatively charged muon forms an atomic system owing to its negative charge, and is finally absorbed into the nucleus or decays to an electron. The lifetimes of muons differ significantly, depending on whether they are trapped by Fe or C atoms, and identifying the elemental content at the muon stoppage position is possible via muon lifetime measurements. The relationship between the muon capture probabilities of C/Fe and the elemental content of C exhibits a good linearity, and the C content in the steel may be quantitatively determined via muon lifetime measurements. Furthermore, by controlling the incident energies of the muons, they may be stopped in each layer of a stacked sample consisting of three types of steel plates with thicknesses of 0.5 mm, and we successfully determined the C contents in the range 0.20 - 1.03 wt% depth-selectively, without sample destruction.

Journal Articles

High temperature gas-cooled reactors

Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.

High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02

As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950$$^{circ}$$C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.

Journal Articles

High peak-current lightning discharges associated with downward terrestrial gamma-ray flashes

Wada, Yuki*; Enoto, Teruaki*; Nakamura, Yoshitaka*; Morimoto, Takeshi*; Sato, Mitsuteru*; Ushio, Tomoo*; Nakazawa, Kazuhiro*; Yuasa, Takayuki*; Yonetoku, Daisuke*; Sawano, Tatsuya*; et al.

Journal of Geophysical Research; Atmospheres, 125(4), p.e2019JD031730_1 - e2019JD031730_11, 2020/02

 Times Cited Count:19 Percentile:80.01(Meteorology & Atmospheric Sciences)

Journal Articles

Gamma-ray glow preceding downward terrestrial gamma-ray flash

Wada, Yuki*; Enoto, Teruaki*; Nakamura, Yoshitaka*; Furuta, Yoshihiro; Yuasa, Takayuki*; Nakazawa, Kazuhiro*; Morimoto, Takeshi*; Sato, Mitsuteru*; Matsumoto, Takahiro*; Yonetoku, Daisuke*; et al.

Communications Physics (Internet), 2(1), p.67_1 - 67_9, 2019/06

 Times Cited Count:41 Percentile:93.33(Physics, Multidisciplinary)

Journal Articles

Occupation sites and valence states of Co dopants in (La, Co)-codoped M-type Sr ferrite; $$^{57}$$Fe and $$^{59}$$Co nuclear magnetic resonance studies

Sakai, Hironori; Hattori, Taisuke; Tokunaga, Yo; Kambe, Shinsaku; Ueda, Hiroaki*; Tanioku, Yasuaki*; Michioka, Chishiro*; Yoshimura, Kazuyoshi*; Takao, Kenta*; Shimoda, Aiko*; et al.

Physical Review B, 98(6), p.064403_1 - 064403_10, 2018/08

 Times Cited Count:10 Percentile:46.45(Materials Science, Multidisciplinary)

To specify preferential occupation sites of Co substituents and to clarify charge and spin states of Co ions in (La, Co)-cosubstituted hexagonal magnetoplumbite-type (M-type) Sr ferrite, $$^{57}$$Fe and $$^{59}$$Co nuclear magnetic resonance (NMR) spectra are measured under zero and external magnetic fields using powdered and single crystalline specimens. To a considerable degree, the charge compensation between La$$^{3+}$$ and Co$$^{2+}$$ works in the equal (La, Co)-codoped case, where more than half of the Co ions are considered to be present in the minority spin $$4f_1$$ sites at the center of the oxygen tetrahedra, with the $$S$$ = 3/2 state carrying a small orbital moment owing to spin-orbit interaction. The remaining small number of high-spin Co$$^{2+}$$ ($$S$$ = 3/2, $$L$$ = 1) ions with unquenched orbital moments would be distributed to the other octahedral $$12k$$, $$2a$$, and $$4f_2$$ sites.

Journal Articles

Materials and Life Science Experimental Facility at the Japan Proton Accelerator Research Complex, 3; Neutron devices and computational and sample environments

Sakasai, Kaoru; Sato, Setsuo*; Seya, Tomohiro*; Nakamura, Tatsuya; To, Kentaro; Yamagishi, Hideshi*; Soyama, Kazuhiko; Yamazaki, Dai; Maruyama, Ryuji; Oku, Takayuki; et al.

Quantum Beam Science (Internet), 1(2), p.10_1 - 10_35, 2017/09

Neutron devices such as neutron detectors, optical devices including supermirror devices and $$^{3}$$He neutron spin filters, and choppers are successfully developed and installed at the Materials Life Science Facility (MLF) of the Japan Proton Accelerator Research Complex (J-PARC), Tokai, Japan. Four software components of MLF computational environment, instrument control, data acquisition, data analysis, and a database, have been developed and equipped at MLF. MLF also provides a wide variety of sample environment options including high and low temperatures, high magnetic fields, and high pressures. This paper describes the current status of neutron devices, computational and sample environments at MLF.

Journal Articles

Fast heating of cylindrically imploded plasmas by petawatt laser light

Nakamura, Hirotaka*; Sentoku, Yasuhiko*; Matsuoka, Takeshi*; Kondo, Kiminori; Nakatsutsumi, Motoaki*; Norimatsu, Takayoshi*; Shiraga, Hiroyuki*; Tanaka, Kazuo*; Kodama, Ryosuke*

Physical Review Letters, 100(16), p.165001_1 - 165001_4, 2008/04

 Times Cited Count:15 Percentile:64.43(Physics, Multidisciplinary)

We produced cylindrically imploded plasmas, which have the same density-radius product of the imploded plasma $$rho$$R with the compressed core in the fast ignition experiment and demonstrated efficient fast heating of cylindrically imploded plasmas with an ultraintense laser light. The coupling efficiency from the laser to the imploded column was 14%-21%, implying strong collimation of energetic electrons over a distance of 300 micron of the plasma. Particle-in-cell simulation shows confinement of the energetic electrons by self-generated magnetic and electrostatic fields excited along the imploded plasmas, and the efficient fast heating in the compressed region.

JAEA Reports

Depth Trend of Chemical Characteristics of Bentonite Deposit in Contact with River Water; Sampling and Analytical Results

Saji, Shinichi*; Ito, Masakazu*; Shibata, Masahiro; Jintoku, Takashi*; Isogai, Takeshi*

JNC TN8400 2005-017, 86 Pages, 2005/09

JNC-TN8400-2005-017.pdf:7.5MB

Porewater chemistry in Buffer Material is one of the most important information for assessment of corrosion behavior on the overpack, and of solubility and sorption of nuclides in the buffer etc. In the Second Progress Report of HLW in Japan (H12 Report), porewater chemistry is estimated by batch modeling calculation based on the batch experiment. However, it is expected that, in the disposal vault, temporal-spatial evolution of porewater chemistry occurrs. After H12 report, JNC started experimental study and modeling work for further understanding of the chemical evolution. However, modeling for long term evaluation of porewater chemistry is calculated on the basis of the short term laboratory experiment. Thus, the long term reliability of the model needs to be verified by comparing natural analogue.In this study, bentonite deposit under the river bed was sampled as function of depth by boring. At the sampling point, the river improvement was carried out in 1987 and river water contact with bentonite deposit since then. Mineral composition, chemical composition, inter layer cation concentration, CEC and methylene blue adsorption etc. of the sample are measured.As a result, erosion of the smectite, decreasing of pH and leaching out of SO4 are obsereved. However, clear trend of the depth direction is not obtained for the reason of natural inhomogeneous system.

Journal Articles

Current status of system development to provide the databases of nuclides migration

Sasamoto, Hiroshi; Yoshida, Yasushi*; Isogai, Takeshi*; Suyama, Tadahiro*; Jintoku, Takashi*; Shibata, Masahiro; Yui, Mikazu

Saikuru Kiko Giho, (28), p.27 - 33, 2005/09

JNC has developed the databases of nuclides migration for safety assessment of high-level radioactive waste (HLW), and the databases have been used in the second progress report to present the technical reliability of HLW geological disposal in Japan. The technical level and applicability of databases developed by JNC have been evaluated highly not only in Japan but also in overseas. Thus we have performed the followings in order to provide the databases broadly in the word and to promote the use of databases; 1) development of tools to convert the database format from geochemical code PHREEQE to PHREEQC, GWB and EQ3/6, 2) open the web site including the databases to the public. As a result, a down-load system of databases from web site has been applied and the database users have significantly increased. Additionally it has been performed that we consider the useful comments from database user for modification and/or update of databases.

JAEA Reports

Determination of the Porewater Compositions in Compacted Bentonite -Results of Experiment using Distilled Water, Synthesized Seawater and a Low-Alkaline Cement Solution-

Isogai, Takeshi*; Jintoku, Takashi; Sasamoto, Hiroshi

JNC TN8400 2003-050, 74 Pages, 2004/03

JNC-TN8400-2003-050.pdf:5.85MB

We determined the pH and chemical compositions of porewaters in compacted bentonite as a function of time. The experiments were carried out using the low-decolorant pH test papers and high-absorbancy pads embedded in compacted bentonite (Kunigel-V1R=100[%]) having dry densities of 1.6 [g/cm$$^{3}$$]. We also measured the chemical composition and exchangeable cation concentrations of the bentonite after the experiments. The experiments were conducted in a controlled-atmosphere glove box (O$$_{2}$$(g) content is less than 1[ppm]) using distilled water, synthesized seawater and a low-alkaline cement porewater (i.e., HFSC: High Flyash contained Silica fume Cement) as initial solutions. The pH of the distilled water and synthesized seawater was adjusted to pH=9 by adding NaOH solution. Distilled water was reacted with crushed HFSC to produce a solution representing low-alkaline cement solution (pH= about 11). - Distilled water: The pH of porewaters further away from the interface did not vary significantly (pH = 8.0 to 9.0), but the pH of porewaters near the infiltration interface slightly decreased (pH = 7.5-8.5 $$rightarrow$$ pH = 7.0-8.0). - Synthesized seawater: The pH values were roughly constant at the interface between 6.5 and 7.0, but the pH of porewaters further away from the interface slightly decreased with time (pH = 6.5-7.0 $$rightarrow$$ pH = 6.0-6.5). - HFSC solution: Like the experiment with involving distilled water, the pH of porewaters contacted with HFSC solution further away from the interface were roughly constant between 8.5 and 10.0, but the pH of porewaters near the infiltration surface significantly decreased with time from pH = 9.5 to pH = 7.5-8.5. Although the determination of porewater chemistry in compacted bentonite was carried out, it was difficult to obtain the quantitative profile for variation during the experiment except the experiment using synthesized seawater.

Journal Articles

Plan for first phase of safety demonstration tests of the High Temperature Engineering Test Reactor (HTTR)

Tachibana, Yukio; Nakagawa, Shigeaki; Takeda, Takeshi; Saikusa, Akio; Furusawa, Takayuki; Takamatsu, Kuniyoshi; Sawa, Kazuhiro; Iyoku, Tatsuo

Nuclear Engineering and Design, 224(2), p.179 - 197, 2003/09

 Times Cited Count:13 Percentile:64.72(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Heat removal performance of auxiliary cooling system for the High Temperature Engineering Test Reactor during scrams

Takeda, Takeshi; Tachibana, Yukio; Iyoku, Tatsuo; Takenaka, Satsuki*

Annals of Nuclear Energy, 30(7), p.811 - 830, 2003/05

 Times Cited Count:1 Percentile:10.89(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Rise-to-power test in High Temperature Engineering Test Reactor; Test progress and summary of test results up to 30MW of reactor thermal power

Nakagawa, Shigeaki; Fujimoto, Nozomu; Shimakawa, Satoshi; Nojiri, Naoki; Takeda, Takeshi; Saikusa, Akio; Ueta, Shohei; Kojima, Takao; Takada, Eiji*; Saito, Kenji; et al.

JAERI-Tech 2002-069, 87 Pages, 2002/08

JAERI-Tech-2002-069.pdf:10.12MB

Rise-to-power test in the HTTR has been performed from April 23rd to June 6th in 2000 as phase 1 test up to 10MW, from January 29th to March 1st in 2001 as phase 2 test up to 20MW in the rated operation mode and from April 14th to June 8th in 2001 as phase 3 test up to 20MW in the high temperature test operation mode. Phase 4 test to achieve the thermal reactor power of 30MW started from October 23rd in 2001. On December 7th it was confirmed that the thermal reactor power reached to 30MW and the reactor outlet coolant temperature reached to 850$$^{circ}$$C. JAERI obtained the certificate of pre-operation test from MEXT because all the pre-operation tests by MEXT were passed successfully. From the test results of rise-up-power test up to 30MW, the performance of reactor and cooling system were confirmed, and it was confirmed that an operation of reactor facility could be performed safely. Some problems to be solved were found through tests. By means of solving them, the reactor operation with the reactor outlet coolant temperature of 950$$^{circ}$$C will be achievable.

JAEA Reports

Safety demonstration test plan of the High Temperature Engineering Test Reactor (HTTR)

Tachibana, Yukio; Nakagawa, Shigeaki; Takeda, Takeshi; Saikusa, Akio; Furusawa, Takayuki; Takamatsu, Kuniyoshi; Nishihara, Tetsuo; Sawa, Kazuhiro; Iyoku, Tatsuo

JAERI-Tech 2002-059, 42 Pages, 2002/08

JAERI-Tech-2002-059.pdf:1.63MB

no abstracts in English

JAEA Reports

Data on loss of off-site electric power simulation tests of the High Temperature Engineering Test Reactor

Takeda, Takeshi; Nakagawa, Shigeaki; Fujimoto, Nozomu; Tachibana, Yukio; Iyoku, Tatsuo

JAERI-Data/Code 2002-015, 39 Pages, 2002/07

JAERI-Data-Code-2002-015.pdf:1.53MB

no abstracts in English

Journal Articles

Procedure to prevent temperature rise of primary upper shielding in high temperature engineering test reactor (HTTR)

Tachibana, Yukio; Hontani, Koji*; Takeda, Takeshi; Saikusa, Akio; Shinozaki, Masayuki; Isozaki, Minoru; Iyoku, Tatsuo; Kunitomi, Kazuhiko

Nuclear Engineering and Design, 201(2-3), p.227 - 238, 2000/10

 Times Cited Count:3 Percentile:26.46(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Countermeasure to prevent temperature rise of primary upper shield in HTTR; Performance test of countermeasures under actural core configuration

Tachibana, Yukio; Hontani, Koji*; Kojima, Takao; Takeda, Takeshi; Emori, Koichi; Saruta, Toru; Iyoku, Tatsuo; Kunitomi, Kazuhiko

JAERI-Tech 2000-026, p.61 - 0, 2000/03

JAERI-Tech-2000-026.pdf:2.18MB

no abstracts in English

Journal Articles

Reports of ITER physics R&D expert meeting

Hosogane, Nobuyuki; Asakura, Nobuyuki; Sugie, Tatsuo; Yoshino, Ryuji; Fukuda, Takeshi; Kusama, Yoshinori; Tobita, Kenji; Ide, Shunsuke; Shimada, Michiya; Sengoku, Seio; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 75(2), p.156 - 161, 1999/02

no abstracts in English

Journal Articles

Performance test of the HTTR

Tanaka, Toshiyuki; Okubo, Minoru; Iyoku, Tatsuo; Kunitomi, Kazuhiko; Takeda, Takeshi; Sakaba, Nariaki; Saito, Kenji

Nihon Genshiryoku Gakkai-Shi, 41(6), p.686 - 698, 1999/00

 Times Cited Count:4 Percentile:34.88(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Report from ITER physics R&D expert meeting

Fukuda, Takeshi; Wakatani, Masahiro*; Toi, Kazuo*; Takizuka, Tomonori; Miura, Yukitoshi; Ogawa, Yuichi*; Takamura, Shuichi*; Oyabu, Nobuyoshi*; Hosogane, Nobuyuki; Sengoku, Seio; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 74(8), p.885 - 887, 1998/08

no abstracts in English

37 (Records 1-20 displayed on this page)