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Journal Articles

Applicability of $$K_{d}$$ for modelling dissolved $$^{137}$$Cs concentrations in Fukushima river water; Case study of the upstream Ota River

Sakuma, Kazuyuki; Tsuji, Hideki*; Hayashi, Seiji*; Funaki, Hironori; Malins, A.; Yoshimura, Kazuya; Kurikami, Hiroshi; Kitamura, Akihiro; Iijima, Kazuki; Hosomi, Masaaki*

Journal of Environmental Radioactivity, 184-185, p.53 - 62, 2018/04

 Times Cited Count:5 Percentile:52.92(Environmental Sciences)

A study is presented on the applicability of the distribution coefficient ($$K_{d}$$) absorption/desorption model to simulate dissolved $$^{137}$$Cs concentrations in Fukushima river water. The simulation results were in good agreement with the observations on water and suspended sediment fluxes, and on particulate bound $$^{137}$$Cs concentrations under both ambient and high flow conditions. By contrast the measured concentrations of dissolved $$^{137}$$Cs in the river water were much harder to reproduce with the simulations. By tuning the $$K_{d}$$ values for large particles, it was possible to reproduce the mean dissolved $$^{137}$$Cs concentrations during base flow periods (observation: 0.32 Bq/L, simulation: 0.36 Bq/L). However neither the seasonal variability in the base flow dissolved $$^{137}$$Cs concentrations (0.14-0.53 Bq/L), nor the peaks in concentration that occurred during storms (0.18-0.88 Bq/L, mean: 0.55 Bq/L), could be reproduced with realistic simulation parameters.

JAEA Reports

Status of study of long-term assessment of transport of radioactive contaminants in the environment of Fukushima; As a part of dissemination of evidence-based information

Tsuruta, Tadahiko; Niizato, Tadafumi; Nakanishi, Takahiro; Dohi, Terumi; Nakama, Shigeo; Funaki, Hironori; Misono, Toshiharu; Oyama, Takuya; Kurikami, Hiroshi; Hayashi, Seiji*; et al.

JAEA-Review 2017-018, 86 Pages, 2017/10

JAEA-Review-2017-018.pdf:17.58MB

Since the accidents at Fukushima Daiichi Nuclear Power Plant following the Tohoku Region Pacific Coast Earthquake on March 11th, 2011, Fukushima Environmental Safety Center has carried out research on natural mobilization of radionuclide (especially radiocesium) and future forecast from forest to water system and surrounding residential areas. The report summarizes the latest results that have been accumulated from each study field, of our agency together with the other related research organizations. The contents of the report is to be used as evidence-based information for the QA-styled pages in the website of JAEA Sector of Fukushima Research and Development at the time of next renewal.

Journal Articles

Ultra-high temperature tensile properties of ODS steel claddings under severe accident conditions

Yano, Yasuhide; Tanno, Takashi; Oka, Hiroshi; Otsuka, Satoshi; Inoue, Toshihiko; Kato, Shoichi; Furukawa, Tomohiro; Uwaba, Tomoyuki; Kaito, Takeji; Ukai, Shigeharu*; et al.

Journal of Nuclear Materials, 487, p.229 - 237, 2017/04

 Times Cited Count:17 Percentile:3.04(Materials Science, Multidisciplinary)

Ultra-high temperature ring tensile tests were carried out to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions; temperatures ranged from room temperature to 1400$$^{circ}$$C which is near the melting point of core materials. The experimental results showed that tensile strength of 9Cr-ODS steel claddings was highest in the core materials at the ultra-high temperatures between 900 and 1200$$^{circ}$$C, but that there was significant degradation in tensile strength of 9Cr-ODS steel claddings above 1200$$^{circ}$$C. This degradation was attributed to grain boundary sliding deformation with $$gamma$$/$$delta$$ transformation, which was associated with reduced ductility. On the other hand, tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 $$^{circ}$$C unlike the other tested materials. Present study includes the result of "R&D of ODS ferritic steel fuel cladding for maintaining fuel integrity at the high temperature accident condition" entrusted to Hokkaido University by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).

Journal Articles

Evaluation on tolerance to failure of ODS ferritic steel claddings at the accident conditions of fast reactors

Uwaba, Tomoyuki; Yano, Yasuhide; Otsuka, Satoshi; Naganuma, Masayuki; Tanno, Takashi; Oka, Hiroshi; Kato, Shoichi; Kaito, Takeji; Ukai, Shigeharu*; Kimura, Akihiko*; et al.

Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 7 Pages, 2017/04

Tolerance of fast rector fuel elements to failure in the typical accident conditions was evaluated for the oxide-dispersion-strengthened (ODS) ferritic steel claddings that are candidate of the cladding material for advanced fast reactors. The evaluation was based on the cladding creep damage, which was quantified by the cumulative damage fractions (CDFs). It was shown that the CDFs of the ODS ferritic steel cladding were substantially lower than the breach limit of 1.0 in the loss of flow and transient over power conditions until a passive reactor shutdown system operates.

Journal Articles

Progress report of Japanese simulation research projects using the high-performance computer system Helios in the International Fusion Energy Research Centre

Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.

Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03

The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.

Journal Articles

Information on ITER Project, 56

Ohara, Hiroshi; Hayashi, Jennifer*

Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.236 - 237, 2016/03

no abstracts in English

Journal Articles

Genome sequence analysis of high ethyl caproate producing sake yeasts generated by ion beam breeding, 2

Masubuchi, Takashi*; Toguchi, Kazuki*; Hayashi, Hidenori*; Ikenaga, Hiroshi*; Sato, Katsuya; Ono, Yutaka

JAEA-Review 2015-022, JAEA Takasaki Annual Report 2014, P. 106, 2016/02

Journal Articles

Information on ITER Project, 55

Ohara, Hiroshi; Moriyama, Setsuko*; Hayashi, Jennifer*

Purazuma, Kaku Yugo Gakkai-Shi, 92(1), p.48 - 50, 2016/01

no abstracts in English

Journal Articles

Information on ITER Project, 54

Ohara, Hiroshi; Moriyama, Setsuko*; Hayashi, Jennifer*

Purazuma, Kaku Yugo Gakkai-Shi, 91(11), p.741 - 742, 2015/11

no abstracts in English

Journal Articles

Information on ITER Project, 53

Hayashi, Jennifer*; Moriyama, Setsuko*; Ohara, Hiroshi

Purazuma, Kaku Yugo Gakkai-Shi, 91(9), P. 620, 2015/09

no abstracts in English

Journal Articles

Genome analysis of high ethyl caproate producing sake yeasts generated by ion beam breeding

Masubuchi, Takashi*; Hyuga, Hirokazu*; Ueda, Ryoshiro; Hayashi, Hidenori*; Ikenaga, Hiroshi*; Sato, Katsuya; Ono, Yutaka

JAEA-Review 2014-050, JAEA Takasaki Annual Report 2013, P. 123, 2015/03

Journal Articles

Signal evaluations using singular value decomposition for Thomson scattering diagnostics

Tojo, Hiroshi; Yamada, Ichihiro*; Yasuhara, Ryo*; Yatsuka, Eiichi; Funaba, Hisamichi*; Hatae, Takaki; Hayashi, Hiroshi*; Itami, Kiyoshi

Review of Scientific Instruments, 85(11), p.11D865_1 - 11D865_3, 2014/11

 Times Cited Count:1 Percentile:92.51(Instruments & Instrumentation)

Journal Articles

R&D status on water cooled ceramic breeder blanket technology

Enoeda, Mikio; Tanigawa, Hisashi; Hirose, Takanori; Nakajima, Motoki; Sato, Satoshi; Ochiai, Kentaro; Konno, Chikara; Kawamura, Yoshinori; Hayashi, Takumi; Yamanishi, Toshihiko; et al.

Fusion Engineering and Design, 89(7-8), p.1131 - 1136, 2014/10

 Times Cited Count:17 Percentile:12.12(Nuclear Science & Technology)

The development of a Water Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) is being performed as one of the most important steps toward DEMO blanket in Japan. Regarding the fabrication technology development using F82H, the fabrication of a real scale mockup of the back wall of TBM was completed. Also the assembling of the complete box structure of the TBM mockup and planning of the pressurization testing was studied. The development of advanced breeder and multiplier pebbles for higher chemical stability was performed for future DEMO blanket application. From the view point of TBM test result evaluation and DEMO blanket performance design, the development of the blanket tritium simulation technology, investigation of the TBM neutronics measurement technology and the evaluation of tritium production and recovery test using D-T neutron in the Fusion Neutronics Source (FNS) facility has been performed.

Journal Articles

Relaxation behavior of laser-peening residual stress under tensile loading investigated by X-ray and neutron diffraction

Akita, Koichi; Hayashi, Kengo*; Takeda, Kazuya*; Sano, Yuji*; Suzuki, Hiroshi; Moriai, Atsushi; Oya, Shinichi*

Mechanical Engineering Journal (Internet), 1(4), p.SMM0029_1 - SMM0029_8, 2014/08

Compressive residual stresses induced by peening techniques improve the strength properties of steels, such as fatigue and stress corrosion cracking. However, the compressive residual stress might be reduced owing to thermal and mechanical loading in-service. In this study, the behavior of surface and internal residual stresses of a laser-peened ferritic steel under quasi-static tensile loading was investigated by X-ray and neutron diffraction. The complementary use of these diffraction techniques provided decisive experimental evidence for elucidating the relaxation process. The critical applied stress of peened samples subjected to a tensile loading can be estimated from the von Misses yield criterion with the maximum tensile residual stress inside the sample.

Journal Articles

Improvement of the position monitor using white light interferometer for measuring precise movement of compact ERL superconducting cavities in cryomodule

Sakai, Hiroshi*; Enami, Kazuhiro*; Furuya, Takaaki*; Sato, Masato*; Shinoe, Kenji*; Umemori, Kensei*; Sawamura, Masaru; Cenni, E.*; Aoto, Tomohiro*; Hayashi, Kyohei*; et al.

Proceedings of 5th International Particle Accelerator Conference (IPAC '14) (Internet), p.1787 - 1789, 2014/07

Alignment of superconducting cavities is one of the important issues for linear collider and/or future light source like ERL and X-FEL. To measure the cavity displacement under cooling to liquid He temperature more precisely, we newly developed the position monitor based on the measurement of the interference of light between the measurement target and the reference point. We applied this monitor to the main linac cryomodule of Compact ERL (cERL) and successfully measured the displacement during 2 K cooling with the resolution of 10 $$mu$$m.

Journal Articles

Precise measurement of superconducting cavity movement in cryomodule by the position monitor using white light interferometer

Sakai, Hiroshi*; Aoto, Tomohiro*; Enami, Kazuhiro*; Furuya, Takaaki*; Sato, Masato*; Shinoe, Kenji*; Umemori, Kensei*; Sawamura, Masaru; Cenni, E.*; Hayashi, Kyohei*; et al.

Proceedings of 16th International Conference on RF Superconductivity (SRF 2013) (Internet), p.291 - 296, 2014/02

Alignment of superconducting cavities is one of the important issues for linear collider and/or future light source like ERL and X-FEL. To measure the cavity displacement under cooling to liquid He temperature more precisely, we newly developed the position monitor by using white light interferometer. This monitor is based on the measurement of the interference of light between the measurement target and the reference point. It can measure the position from the outside of the cryomodule. We applied this monitor to the main linac cryomodule of Compact ERL (cERL) and successfully measured the displacement during 2 K cooling with the resolution of 10 $$mu$$m.

Journal Articles

Overview of materials research and IFMIF-EVEDA under the Broader Approach framework

Nishitani, Takeo; Tanigawa, Hiroyasu; Yamanishi, Toshihiko; Clement Lorenzo, S.*; Baluc, N.*; Hayashi, Kimio; Nakajima, Noriyoshi*; Kimura, Haruyuki; Sugimoto, Masayoshi; Heidinger, R.*; et al.

Fusion Science and Technology, 62(1), p.210 - 218, 2012/07

 Times Cited Count:3 Percentile:69.14(Nuclear Science & Technology)

Recent progress in the material related researches and the IFMIF/EVEDA project, which are carried out under the Broader Approach (BA) framework, is reported. In the International Fusion Energy Research Center (IFERC) project of BA, the R&D building was completed March 2010 at the Rokkasho BA site. R&Ds on reduced activation ferritic/ martensitic (RAFM) steels as structural material, SiC/SiC composites as a flow channel insert material and/or alternative structural material, advanced tritium breeders and neutron multipliers, and tritium technology relevant to the DEMO operational condition are progressed in Japan and EU. In the IFMIF/EVEDA project, the fabrication of the injector for the IFMIF prototype accelerator was completed at the CEA Saclay, and the first proton beam was obtained in May, 2011. The IFMIF lithium target test loop was completed in March 2011, and a lithium flow of 5 m/s was obtained.

Journal Articles

Past 25 years results for large amount of tritium handling technology in JAEA

Yamanishi, Toshihiko; Yamada, Masayuki; Suzuki, Takumi; Kawamura, Yoshinori; Nakamura, Hirofumi; Iwai, Yasunori; Kobayashi, Kazuhiro; Isobe, Kanetsugu; Inomiya, Hiroshi; Hayashi, Takumi

Fusion Science and Technology, 60(3), p.1083 - 1087, 2011/10

 Times Cited Count:2 Percentile:78.31(Nuclear Science & Technology)

Tritium Process Laboratory (TPL) in Japan Atomic Energy Agency has been established as the only test facilities to handle over 1 gram of in Japan. From March 1988, TPL has been operated with tritium, and no tritium release accident has been observed. The average tritium concentration in a stream from a stack of the TPL to environment was 71 Bq/m$$^{3}$$, and was 1/70 of the Japanese regulation value for HTO. The failure data have been analyzed for several main components of the safety systems such as pumps, valves, and monitors. The data on the tritium waste and accountancy has also been accumulated. As a study of the Grants-in-Aid for Scientific Research, these data are analysed and are reported.

Journal Articles

Spatio-temporal mapping; A Technique for overview visualization of time-series datasets

Miyamura, Hiroko; Hayashi, Sachiko*; Suzuki, Yoshio; Takemiya, Hiroshi

Progress in Nuclear Science and Technology (Internet), 2, p.603 - 608, 2011/10

Numerical simulations have recently increased in scale and have often output high dimensional datasets. This makes it difficult for users to quickly grasp physical phenomena involved in such datasets. To overcome this difficulty, we propose a spatio-temporal mapping technique (spatio-temporal map) by using an information visualization technique. The spatio-temporal map is generated by mapping the values of a 3D and time-evolving physical quantity into a 2D space with spatial and temporal axes. Here, 3D spatial information is condensed into one dimension by subdividing a target model with an octree. By using the map, users can quickly find regions of interest (ROI). In addition, users can interactively change several aspects of the map such as its resolution and color coding method. By applying the spatio-temporal map to a full-scale 3D vibration simulator for an entire nuclear power plant, we confirmed that the map is a useful technique to quickly identify appropriate ROI.

JAEA Reports

Document collection of the 23rd Technical Special Committee on Fugen Decommissioning

Otani, Hiroshi; Hayashi, Hirokazu; Kawagoe, Shinji; Hamada, Nobuyuki; Nakamura, Yasuyuki

JAEA-Review 2011-026, 41 Pages, 2011/07

JAEA-Review-2011-026.pdf:7.38MB

In planning and carrying out our decommissioning technical development, "Technical special committee on Fugen decommissioning", which consists of the members well-informed, is established, aiming to make good use of Fugen as a place for technological development which is opened inside and outside the country, as the central point in the energy research and development base making project of Fukui prefecture, and to utilize the outcome in our decommissioning to the technical development effectively. This report compiles presentation materials "Current Situation of Fugen Decommissioning", "Preparatory Situation for Operation of Clearance System", "Examined Situation of Nuclear Reactor Dismantlement Technology" of the 23rd Technical special committee on Fugen decommissioning which held on March 11, 2011.

126 (Records 1-20 displayed on this page)