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Journal Articles

Study on current US views on bilateral civilian nuclear cooperation agreements

Tazaki, Makiko; Tamai, Hiroshi; Shimizu, Ryo; Kimura, Takashi; Kitade, Yuta; Nakanishi, Hiroaki; Suda, Kazunori

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 7 Pages, 2018/11

no abstracts in English

Journal Articles

A Study on the Tendencies on the Member States from which Broader Conclusion (BC) Has Been Drawn and on Those from which BC Has Not Been Drawn Yet by the International Atomic Energy Agency: Extracting Possible Requirements for Drawing the BC

Nakanishi, Hiroaki; Kimura, Takashi; Shimizu, Ryo; Kitade, Yuta; Tazaki, Makiko; Tamai, Hiroshi; Suda, Kazunori

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2018/11

To extract the possible requirements for the Broader Conclusion (BC) drawn by the IAEA in the Member States, this study is to conduct the comparative analysis of the tendencies on the Member States from which the BC has been drawn and those from which the BC has not been drawn yet.

Journal Articles

Summary of research result of State Level Concept (SLC)

Kimura, Takashi; Tazaki, Makiko; Kitade, Yuta; Shimizu, Ryo; Tamai, Hiroshi; Nakanishi, Hiroaki; Suda, Kazunori

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 5 Pages, 2018/11

This is the summary of research result of State Level Concept (SLC) which has been developed and conducted by the IAEA and a major purpose of the research reported here is to promote the nuclear operator's understandings for the importance of Broder Conclusion drawn continuously by the IAEA under SLC.

Journal Articles

Study on elements of establishing the regional safeguards

Kitade, Yuta; Tamai, Hiroshi; Tazaki, Makiko; Shimizu, Ryo; Kimura, Takashi; Nakanishi, Hiroaki; Suda, Kazunori

Nihon Kaku Busshitsu Kanri Gakkai Dai-39-Kai Nenji Taikai Rombunshu (Internet), 9 Pages, 2018/11

Regional Safeguards is considered as one of the measures for strengthening IAEA safeguards and its concept is recognized at NPT Review Conference and also NSG Guidelines amended in 2011. This Study examines the elements for the proper establishment of Regional Safeguards.

Journal Articles

Evaluation of sediment and $$^{137}$$Cs redistribution in the Oginosawa River catchment near the Fukushima Dai-ichi Nuclear Power Plant using integrated watershed modeling

Sakuma, Kazuyuki; Malins, A.; Funaki, Hironori; Kurikami, Hiroshi; Niizato, Tadafumi; Nakanishi, Takahiro; Mori, Koji*; Tada, Kazuhiro*; Kobayashi, Takamaru*; Kitamura, Akihiro; et al.

Journal of Environmental Radioactivity, 182, p.44 - 51, 2018/02

 Times Cited Count:2 Percentile:38.23(Environmental Sciences)

The Oginosawa River catchment lies 15 km south-west of the Fukushima Dai-ichi nuclear plant. The General-purpose Terrestrial Fluid-flow Simulator (GETFLOWS) code was used to study sediment and $$^{137}$$Cs redistribution within the catchment. Cesium-137 input to watercourses came predominantly from land adjacent to river channels and forest gullies. Forested areas far from the channels only made a minor contribution to $$^{137}$$Cs input to watercourses, total erosion of between 0.001-0.1 mm from May 2011 to December 2015. The 2.3-6.9% y$$^{-1}$$ decrease in the amount of $$^{137}$$Cs in forest topsoil over the study period can be explained by radioactive decay (approximately 2.3% y$$^{-1}$$), along with a migration downwards into subsoil and a small amount of export. The amount of $$^{137}$$Cs available for release from land adjacent to rivers is expected to be lower in future than compared to this study period, as the simulations indicate a high depletion of inventory from these areas.

Journal Articles

Localization of cesium on montmorillonite surface investigated by frequency modulation atomic force microscopy

Araki, Yuki*; Sato, Hisao*; Okumura, Masahiko; Onishi, Hiroshi*

Surface Science, 665, p.32 - 36, 2017/11

 Times Cited Count:2 Percentile:66.35(Chemistry, Physical)

no abstracts in English

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

Numerical study of sediment and $$^{137}$$Cs discharge out of reservoirs during various scale rainfall events

Kurikami, Hiroshi; Funaki, Hironori; Malins, A.; Kitamura, Akihiro; Onishi, Yasuo*

Journal of Environmental Radioactivity, 164, p.73 - 83, 2016/11

AA2015-0827.pdf:2.61MB

 Times Cited Count:5 Percentile:55.17(Environmental Sciences)

We performed simulations using the three-dimensional finite volume code FLESCOT to understand sediment and radiocesium transport in generic models of reservoirs with parameters similar to those in Fukushima Prefecture. The simulations model turbulent water flows, transport of sediments with different grain sizes, and radiocesium migration both in dissolved and particulate forms. To demonstrate the validity of the modeling approach for the Fukushima environment, we performed a test simulation of the Ogaki Dam reservoir over a typhoon. We simulated a set of generic model reservoirs systematically varying features such as flood intensity, reservoir volume and the radiocesium distribution coefficient. The results ascertain how these features affect the amount of sediment or $$^{137}$$Cs discharge downstream from the reservoirs, and the forms in which $$^{137}$$Cs is discharged. Silt carries the majority of the radiocesium in the larger flood events, while the clay-sorbed followed by dissolved forms are dominant in smaller events. The results can be used to derive indicative values of discharges from Fukushima reservoirs under arbitrary flood events.

Journal Articles

The Operation status of the superconducting cavity for CERL main linac; Toward the deep understanding inside the superconducting cavity with high current beam

Numata, Naoto*; Asakawa, Tomoyuki*; Sakai, Hiroshi*; Umemori, Kensei*; Furuya, Takaaki*; Shinoe, Kenji*; Enami, Kazuhiro*; Egi, Masato*; Sakanaka, Shogo*; Michizono, Shinichiro*; et al.

Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.566 - 570, 2015/09

no abstracts in English

Journal Articles

Development of fast reactor containment safety analysis code, CONTAIN-LMR, 1; Outline of development project

Miyahara, Shinya; Seino, Hiroshi; Ohno, Shuji; Konishi, Kensuke

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 5 Pages, 2015/05

A CONTAIN-LMR code has been developed in JAEA for application to PRA of LMFRs since the original CONTAIN code had been introduced from SNL of U.S. in 1982. The code is a best-estimate, integrated analysis tool for predicting the physical, chemical and radiological conditions inside a containment building of LMFRs following a severe accident with reactor vessel melt-through. The code is also able to predict the source term to the environment in the accident. This code can treat many important phenomena consistently such as sodium fire, radioactive aerosol behavior, hydrogen burn, sodium-concrete reaction and core debris-concrete interaction occurred in the accident with inter-cell heat and mass flow under the multiple cell geometry. This paper describes the chronology of the code development in JAEA briefly as an introduction, and after that, the outline of computational models in the code, the examples of the code validation, and the future plan of the code application are described.

JAEA Reports

Annual report of Nuclear Emergency Assistance and Training Center; April 1, 2013 - March 31, 2014

Sato, Takeshi; Muto, Shigeo; Akiyama, Kiyomitsu; Aoki, Kazufumi; Okamoto, Akiko; Kawakami, Takeshi; Kume, Nobuhide; Nakanishi, Chika; Koie, Masahiro; Kawamata, Hiroyuki; et al.

JAEA-Review 2014-048, 69 Pages, 2015/02

JAEA-Review-2014-048.pdf:13.91MB

JAEA was assigned as a designated public institution under the Disaster Countermeasures Basic Act and under the Armed Attack Situations Response Act. Based on these Acts, the JAEA has the responsibility of providing technical support to the national government and/or local governments in case of disaster responses or response in the event of a military attack, etc. In order to fulfill the tasks, the JAEA has established the Emergency Action Plan and the Civil Protection Action Plan. In case of a nuclear emergency, NEAT dispatches specialists of JAEA, supplies the national government and local governments with emergency equipment and materials, and gives technical advice and information. In normal time, NEAT provides various exercises and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response institutions of the national and local governments, police, fire fighters, self-defense forces, etc. in addition to the JAEA itself. The NEAT also researches nuclear disaster preparedness and response, and cooperates with international organizations. In the FY2013, the NEAT accomplished the following tasks: (1) Technical support activities as a designated public institution in cooperation with the national and local governments, etc. (2) Human resource development, exercise and training of nuclear emergency response personnel for the national and local governments, etc. (3) Researches on nuclear disaster preparedness and response, and sending useful information (4) International contributions to Asian countries on nuclear disaster preparedness and response in collaboration with the international organizations

Journal Articles

Mathematical Modeling of Radioactive Contaminants in the Fukushima Environment

Kitamura, Akihiro; Kurikami, Hiroshi; Yamaguchi, Masaaki; Oda, Yoshihiro; Saito, Tatsuo; Kato, Tomoko; Niizato, Tadafumi; Iijima, Kazuki; Sato, Haruo; Yui, Mikazu; et al.

Nuclear Science and Engineering, 179(1), p.104 - 118, 2015/01

 Times Cited Count:4 Percentile:43.49(Nuclear Science & Technology)

The prediction of the distribution and fate of radioactive materials eventually deposited at surface in the Fukushima area is one of the main objectives and expected to be achieved in an efficient manner. In order to make such prediction, a number of mathematical models of radioactive contaminants, with particular attention on cesium, on the land and in rivers, lakes, and estuaries in the Fukushima area are developed. Simulation results are examined with the field investigations simultaneously implemented. The basic studies of the adsorption/absorption mechanism of cesium and soils have been performed to shed light on estimating distribution coefficient between dissolved contaminant and particulate contaminant.

Journal Articles

Development of natural circulation analytical model in Super-COPD code and evaluation of core cooling capability in Monju during a station blackout

Yamada, Fumiaki; Fukano, Yoshitaka; Nishi, Hiroshi; Konomura, Mamoru

Nuclear Technology, 188(3), p.292 - 321, 2014/12

 Times Cited Count:8 Percentile:25.95(Nuclear Science & Technology)

The capability of natural circulation for core cooling has been evaluated in detail for a station blackout (SBO) event induced by an earthquake and a subsequent tsunami hit. The evaluation was prompted by the accident at the Fukushima Daiichi Nuclear Power Station of Tokyo Electric Power Company. The plant dynamics computer code Super-COPD was used for the evaluation, which has been validated by analyses of preliminary test results on the natural circulation in Monju. As a result, it was concluded that natural circulation of the sodium coolant will enable the decay heat from the core to be removed under such an SBO condition.

Journal Articles

Sediment and $$^{137}$$Cs behaviors in the Ogaki Dam Reservoir during a heavy rainfall event

Kurikami, Hiroshi; Kitamura, Akihiro; Yokuda, Satoru*; Onishi, Yasuo*

Journal of Environmental Radioactivity, 137, p.10 - 17, 2014/11

 Times Cited Count:17 Percentile:31.53(Environmental Sciences)

Journal Articles

In situ XAFS and HAXPES analysis and theoretical study of cobalt polypyrrole incorporated on carbon (CoPPyC) oxygen reduction reaction catalysts for anion-exchange membrane fuel cells

Asazawa, Koichiro*; Kishi, Hirofumi*; Tanaka, Hirohisa*; Matsumura, Daiju; Tamura, Kazuhisa; Nishihata, Yasuo; Saputro, A. G.*; Nakanishi, Hiroshi*; Kasai, Hideaki*; Artyushkova, K.*; et al.

Journal of Physical Chemistry C, 118(44), p.25480 - 25486, 2014/11

 Times Cited Count:11 Percentile:46.5(Chemistry, Physical)

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:15 Percentile:9.29(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

Predicting sediment and cesium-137 discharge from catchments in eastern Fukushima

Kitamura, Akihiro; Yamaguchi, Masaaki; Kurikami, Hiroshi; Yui, Mikazu; Onishi, Yasuo*

Anthropocene, 5, p.22 - 31, 2014/03

Amount of soil and cesium losses in Eastern Fukushima Prefecture is evaluated by a simple and fast simulation model which we developed utilizing the universal soil loss equation and the geographical information system. We focused on the land use factor of the universal soil loss equation in this study. It was estimated that the forest occupies 64% of the total land surface of the study area, but only accounts for 24% of total soil runoff and 33% of total cesium dispersion. The most contributing component comes from the crop field, while the forest becomes the second. Also, calculation was performed for each river basins and results were compared with field monitoring data.

JAEA Reports

Annual report of Nuclear Emergency Assistance and Training Center; April 1, 2012 - March 31, 2013

Sato, Takeshi; Muto, Shigeo; Okuno, Hiroshi; Katagiri, Hiromi; Akiyama, Kiyomitsu; Okamoto, Akiko; Koie, Masahiro; Ikeda, Takeshi; Nemotochi, Toshimasa; Saito, Toru; et al.

JAEA-Review 2013-046, 65 Pages, 2014/02

JAEA-Review-2013-046.pdf:11.18MB

When a nuclear emergency occurs in Japan, the Japan Atomic Energy Agency (JAEA) has the responsibility of providing technical support to the National government, local governments, police, fire stations and nuclear operators etc., because the JAEA has been designated as the Designated Public Institution under the Basic Act on Disaster Control Measures and the Act on Response to Armed Attack Situations, etc.. The Nuclear Emergency Assistance and Training Center (NEAT) of JAEA provides a comprehensive range of technical support activities to an Off-Site Center in case of a nuclear emergency. Specifically, NEAT gives technical advice and information, dispatches specialists as required, and supplies the National Government and local governments with emergency equipments and materials. NEAT provides various exercise and training courses concerning nuclear disaster prevention to those personnel taking an active part in emergency response organizations at normal times. The tasks of NEAT, with its past experiences as a designated public institution including the responses to TEPCO's Fukushima Accident, have been shifted to technical supports to the national government for strengthening its abilities to emergency responses; the NEAT therefore focused on maintenance and operation of its functions, and strengthening its response abilities in cooperation with the national government. This annual report summarized these activities of JAEA/NEAT in the fiscal year 2012.

JAEA Reports

Chemical composition of artificial seawater after leaching tests of irradiated fuel

Tanaka, Kosuke; Suto, Mitsuo; Onishi, Takashi; Akutsu, Yoko; Yoshitake, Tsunemitsu; Yamashita, Shinichiro; Sekioka, Ken*; Ishigamori, Toshio*; Obayashi, Hiroshi; Koyama, Shinichi

JAEA-Research 2013-036, 31 Pages, 2013/12

JAEA-Research-2013-036.pdf:3.31MB

In the accident of Fukushima Daiichi NPPs, the water ingress was performed in order to decrease the reactor temperature. At that time, sea water was temporarily used as a coolant and the water contacted with nuclear fuel directly. It can be supposed that fission products (FP) were easily migrated from the fuel to sea water in this situation and that affect the water quality. The knowledge of leaching behavior, therefore, is necessary for evaluating the integrity of reactor component materials such as steels for pressure containment vessel and for reactor vessel. In order to obtain the fundamental knowledge for leaching behavior of FP in the hot sea water, the leaching tests of irradiated fuel were performed and the leachates were subjected to chemical analysis. It is found that he leaching rate of each nuclides obtained in this study were similar to that of the leaching results simulating the underground water.

Journal Articles

Simulating long-term $$^{137}$$Cs distribution on territory of Fukushima

Kitamura, Akihiro; Yamaguchi, Masaaki; Oda, Yoshihiro; Kurikami, Hiroshi; Onishi, Yasuo*

Transactions of the American Nuclear Society, 109(1), p.153 - 155, 2013/11

Long term $$^{137}$$Cs transport and its future distribution on the territory of Fukushima were predicted based on the USLE and the GIS. By modeling the soil erosion, transport, and deposition, we simulated the future distributions of air dose rates of $$^{137}$$Cs in mSv/h for 2, 6 and 21 years after the accident. The predictions made by METI were compared with the present results. The predictions of relatively high air dose rate areas were consistently matched between the two models over time. However, our model seemed to predict the decreasing rate of the $$^{137}$$Cs concentration with time to be slightly less than that of METI prediction. Some portions of the results obtained in the present study were used to provide influxes of sediments and $$^{137}$$Cs as boundary conditions and lateral inflows for the hydraulic river model.

345 (Records 1-20 displayed on this page)