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Journal Articles

Radiation monitoring using an unmanned helicopter in the evacuation zone around the Fukushima Daiichi Nuclear Power Plant

Sanada, Yukihisa; Kondo, Atsuya*; Sugita, Takeshi*; Nishizawa, Yukiyasu; Yuki, Yoichi*; Ikeda, Kazutaka*; Shoji, Yasunori*; Torii, Tatsuo

Exploration Geophysics, 45(1), p.3 - 7, 2014/11

 Times Cited Count:22 Percentile:27.45(Geochemistry & Geophysics)

The Great East Japan Earthquake on March 11, 2011 generated a series of large tsunami waves that resulted serious damage to the Fukushima Daiichi Nuclear Power Plant (NPP) and a large amount of radioactive materials were discharged from the NPP to the environment. In recent years, technologies for an unmanned helicopter have been developed and applied to various fields. In expectation of the application of the unmanned helicopter to airborne radiation monitoring, we had developed a radiation monitoring system. Then, we measured the radiation level by using unmanned helicopter in soil contaminated areas by radioactive cesium emitted from the NPP to evaluate ambient dose-rate distribution around the areas. Here, we reports on the measurement technique and the result.

Journal Articles

Operation and maintenance experience from the HTTR database

Shimizu, Atsushi; Furusawa, Takayuki; Homma, Fumitaka; Inoi, Hiroyuki; Umeda, Masayuki; Kondo, Masaaki; Isozaki, Minoru; Fujimoto, Nozomu; Iyoku, Tatsuo

Journal of Nuclear Science and Technology, 51(11-12), p.1444 - 1451, 2014/11

 Times Cited Count:1 Percentile:88.23(Nuclear Science & Technology)

JAEA has kept up a data-base system of operation and maintenance experiences of the HTTR. The objective of this system is to share the information obtained operation and maintenance experiences and to make use of lessons learned and knowledge into a design, construction and operation managements of the future HTGR. More than one thousand records have been registered into the system between 1997 and 2012. This paper describes the status of the data-base system, and provides suggestions for improvement from four experiences: (1) performance degradation of helium compressors; (2) malfunction of reserved shutdown system in reactivity control system; (3) maintenance experiences of emergency gas turbine generators; and (4) experiences of the Great East Japan Earthquake. These experiences are extracted from the system as important lessons learned to be expected to apply for design, construction and operation managements of future HTGR.

Journal Articles

The Aerial radiation monitoring in Japan after the Fukushima Daiichi Nuclear Power Plant accident

Sanada, Yukihisa; Sugita, Takeshi; Nishizawa, Yukiyasu; Kondo, Atsuya*; Torii, Tatsuo

Progress in Nuclear Science and Technology (Internet), 4, p.76 - 80, 2014/04

The ambient dose-rate and the deposition concentration of radioactive cesium was measured by using helicopters in the whole area of Japan to investigate the influence of the radioactivity that released in the atmosphere due to the disaster of the Fukushima Daiichi NPP (Nuclear Power Plant), Tokyo Electric Power Company (TEPCO), occurred by the East Japan earthquake and tsunami on March 11, 2011. As a result, the deposition of radioactive cesium on the ground discharged from the Fukushima Daiichi NPP was obtained, and it was clarified that the scattered range of the cesium had been almost limited from the southern part of Tohoku to Kanto areas. The variation distribution of the dose-rate of Japan was also revealed in this measurement.

JAEA Reports

Radiation monitoring using the unmanned helicopter after the accident of the nuclear power plant

Sanada, Yukihisa; Nishizawa, Yukiyasu; Yamada, Tsutomu; Ikeda, Kazutaka*; Matsui, Masashi*; Tsuchida, Kiyofumi; Sato, Yoshiharu; Hirayama, Hirokatsu; Takamura, Yoshihide; Nishihara, Katsuya; et al.

JAEA-Research 2013-049, 129 Pages, 2014/03

JAEA-Research-2013-049.pdf:15.5MB

By the nuclear disaster of Fukushima Daiichi Nuclear Power Plant (NPP), Tokyo Electric Power Company (TEPCO), caused by the East Japan earthquake and the following tsunami occurred on March 11, 2011, a large amount of radioactive materials was released from the NPP. In recent years, technologies for autonomous unmanned helicopters (AUHs) have been developed and applied to natural disasters. In expectation of the application of the AUHs to aerial radiation monitoring, we had developed a remote radiation monitoring system. Then, we measured the radiation level by using unmanned helicopter in soil contaminated areas by radioactive cesium emitted from the NPP to evaluate ambient dose-rate distribution around the areas and to investigate the decontamination effect by the measurements before and after decontamination treatment. Here, we reports on the measurement technique and the result.

JAEA Reports

Investigation of radionuclide distribution using aircraft for surrounding environmental survey from Fukushima Dai-ichi Nuclear Power Plant

Torii, Tatsuo; Sanada, Yukihisa; Sugita, Takeshi; Kondo, Atsuya*; Shikaze, Yoshiaki; Takahashi, Masaki; Ishida, Mutsushi; Nishizawa, Yukiyasu; Urabe, Yoshimi

JAEA-Technology 2012-036, 182 Pages, 2012/12

JAEA-Technology-2012-036.pdf:41.89MB

We carried out aerial radiation monitoring (ARM) of all Japan area in order to investigate the influence of the radio cesium which was emitted into the atmosphere by disaster of the Fukushima Dai-ichi Nuclear Power Plant of Tokyo Electric Power Co., Inc.. AMS can measure a $$gamma$$ ray quickly by flight from 300 m height above the ground. Moreover, ARM has an advantage which can grasp self-possessed quantity distribution of an air dose rate and radioactive cesium in "field", and is visually intelligible. Although there were apparatus and the technique of ARM in our country, sufficient preparations for wide area monitoring were not made. Therefore, it fixed based on the method of the U.S. Department of Energy (DOE) about the method of the conversion to all radiation dose, and the conversion method to radiocesium deposition and the method of mapping. It is possible to discriminate from a background (cosmic-ray, self-contamination and natural nuclides) at the time of western-part-of-Japan measurement by improving of the method in parallel to data acquisition. By this monitoring, it was able to check about the distribution situation of the air dose rate of the Japanese whole region, or the radioactive cesium deposition. Here, the measurement technique and a result are described.

Journal Articles

Distribution of radioactive cesium measured by aerial radiation monitoring

Sanada, Yukihisa; Kondo, Atsuya; Sugita, Takeshi; Torii, Tatsuo

Hoshasen, 38(3), p.137 - 140, 2012/12

We have measured the ambient dose-rate and the deposition amount of radioactive cesium by using four helicopters in the whole area of Japan to investigate the influence of the radioactivity that released in the atmosphere due to the disaster of the Fukushima Dai-ichi NPP (Nuclear Power Plant), Tokyo Electric Power Company (TEPCO), caused by the Tohoku-Pacific Ocean Earthquake and tsunami on March 11, 2011. We report on the measurement technique and the result.

Journal Articles

Orbital excitations in LaMnO$$_3$$ studied by resonant inelastic X-ray scattering

Inami, Toshiya; Fukuda, Tatsuo; Mizuki, Junichiro; Ishihara, Sumio*; Kondo, Hiroshi*; Nakao, Hironori*; Matsumura, Takeshi*; Hirota, Kazuma*; Murakami, Yoichi*; Maekawa, Sadamichi*; et al.

Physical Review B, 67(4), p.045108_1 - 045108_6, 2003/01

 Times Cited Count:56 Percentile:10.63(Materials Science, Multidisciplinary)

We report resonant inelastic x-ray scattering experiments of the orbitally ordered manganite LaMnO$$_3$$. When incident photon energy is tuned near the Mn $$K$$ absorption edge, the spectra reveal three features at 2.5 eV, 8 eV and 11 eV. The 8 eV and 11 eV peaks are ascribed to transitions from the O 2$$p$$ bands to the empty Mn 3$$d$$ and $$4s$$/$$4p$$ bands, respectively. On the other hand, the 2.5 eV peak is considered an orbital excitation across the Mott gap, ${it i.e.}$ an electron excitation from the effective lower Hubbard band with the $$d_{3x^2-r^2}$$ and $$d_{3y^2-r^2}$$ orbital characters to the upper Hubbard band with the $$d_{y^2-z^2}$$ and $$d_{z^2-x^2}$$ ones. The weak dispersion and characteristic azimuthal angle dependence of this excitation are well reproduced by a theory which includes orbital degeneracy and strong electron correlation.

Journal Articles

Staged deployment of the international fusion materials irradiation facility (IFMIF)

Takeuchi, Hiroshi; Sugimoto, Masayoshi; Nakamura, Hiroo; Yutani, Toshiaki*; Ida, Mizuho*; Jitsukawa, Shiro; Kondo, Tatsuo; Matsuda, Shinzaburo; Matsui, Hideki*; Shannon, T. E.*; et al.

Fusion Energy 2000 (CD-ROM), 5 Pages, 2001/00

no abstracts in English

Journal Articles

International strategy for fusion materials development

Ehrlich, K.*; Bloom, E. E.*; Kondo, Tatsuo

Journal of Nuclear Materials, 283-287(1), p.79 - 88, 2000/12

 Times Cited Count:78 Percentile:2.07(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Creep and rupture behavior of hastelloy XR in simulated HTGR helium

*; ; ; Nakajima, Hajime; Kondo, Tatsuo

Nippon Genshiryoku Gakkai-Shi, 36(10), p.967 - 975, 1994/00

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Development of a new Ni-Cr-W superalloy for application to high temperature structures

Tsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo

Proc. of the 5th Conf. on Materials for Advanced Power Engineering,Part I, 0, p.939 - 948, 1994/00

no abstracts in English

Journal Articles

Research and development on materials as base technology in nuclear applications

Kondo, Tatsuo; Hishinuma, Akimichi; Noda, Kenji; Eto, Motokuni; Tsuji, Hirokazu; Nakajima, Hajime; Kiuchi, Kiyoshi; Ono, Hideo; Ogawa, Toru; Omichi, Hideki; et al.

Genshiryoku Kogyo, 39(8), p.1 - 80, 1993/08

no abstracts in English

JAEA Reports

Journal Articles

Development of Ni-Cr-W superalloy for HTGR application

Tsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo

JAERI-M 92-215, p.584 - 598, 1993/01

no abstracts in English

Journal Articles

High-energy/intensity neutron facilities for testing fusion materials

Kondo, Tatsuo; Ono, Hideo; R.A.Jameson*; J.A.Hassberger*

Fusion Engineering and Design, 22, p.117 - 127, 1993/00

 Times Cited Count:6 Percentile:42.69

no abstracts in English

Journal Articles

Statistical analyses of variability/reproducibility of environmentally-assisted cyclic crack growth rate data relative to $$Delta$$K control modes

Tsuji, Hirokazu; ; Nakajima, Hajime; Kondo, Tatsuo

Journal of Nuclear Materials, 202, p.79 - 86, 1993/00

 Times Cited Count:1 Percentile:80.58(Materials Science, Multidisciplinary)

no abstracts in English

Journal Articles

Effects of minor elements on high temperature properties and producibility on Ni-Cr-W superalloys for HTGR application

Tsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo

Proc. of the 2nd ASME/JSME Nuclear Engineering Joint Conf., 1993,Vol. 2, p.167 - 172, 1993/00

no abstracts in English

Journal Articles

Prediction of high-temperarure properties and producibility of Ni-Cr-W superalloys by multiple regression analyses

Tsuji, Hirokazu; Nakajima, Hajime; Kondo, Tatsuo

Proc. of the Int. Conf. on Computer-assisted Materials Design and Process Simulation, p.398 - 403, 1993/00

no abstracts in English

Journal Articles

Research & development of metallic materials for HTGR applications

Nakajima, Hajime; Kondo, Tatsuo

Gensan Semina "Koon Gasuro Kaihatsu To Netsu Riyo Gijutsu No Tembo", p.1 - 12, 1992/02

no abstracts in English

Journal Articles

Concept of Energy Selective Neutron Irradiation Test Facility(ESNIT)

Ono, Hideo; Sugimoto, Masayoshi; ; Noda, Kenji; Kondo, Tatsuo

Nippon Genshiryoku Gakkai-Shi, 34(1), p.33 - 40, 1992/01

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

no abstracts in English

152 (Records 1-20 displayed on this page)