Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Yamada, Junya; Hashimoto, Makoto; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji; Yokoyama, Sumi*; Shimo, Michikuni*
Hoken Butsuri, 52(1), p.5 - 12, 2017/03
The purpose of this study is to improve a quick method for estimation of I concentrations in the air using data measured by monitoring posts in case that a nuclear disaster occurs. In this method, I concentrations were estimated by multiplying I count rates of cloud-shine measured with NaI (Tl) detector by concentration conversion factor. A previous study suggested that it was difficult to determine passing-through time of plume from temporal change of I count rates or dose rate. Our study applies the method for estimating passing-through time of plume from temporal change of noble gas counts. The I concentrations in the air at Oarai center, Japan Atomic Energy Agency resulting from the accident at the Fukushima Daiichi Nuclear Power Plant were estimated by proposal technique. The result of comparison of this method with sampling method for I concentrations in the air were within factor 3.
Yamada, Junya; Hashimoto, Makoto; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji; Yokoyama, Sumi*; Shimo, Michikuni*
Radioisotopes, 65(10), p.403 - 408, 2016/10
The purpose of this study is to develop a quick method for estimation of I concentrations in the air using data measured by monitoring posts. In this method, I concentrations were estimated by multiplying I count rates at the full-energy peak measured with a NaI(Tl) detector by a concentration conversion factor. The concentration conversion factor for monitoring posts in JAEA Oarai Center was calculated with an EGS5 Monte Carlo code. As a result, the concentration conversion factor for an infinite-air-source was 25.7 Bq/m/cps.
Takahashi, Naoki; Yoshinaka, Kazuyuki; Harada, Akio; Yamanaka, Atsushi; Ueno, Takashi; Kurihara, Ryoichi; Suzuki, Soju; Takamatsu, Misao; Maeda, Shigetaka; Iseki, Atsushi; et al.
Nihon Genshiryoku Gakkai Homu Peji (Internet), 64 Pages, 2016/00
no abstracts in English
Seya, Natsumi; Hashimoto, Makoto; Nemoto, Koji*; Shimizu, Takehiko; Takasaki, Koji
Hoken Butsuri, 49(1), p.29 - 38, 2014/03
Evaluation of annual average of radionuclide concentration in surface air obtained from atmospheric dispersion factor is intended to determine a public dose as a primary source for the safety analysis of nuclear facilities in normal operation. Oarai Research and Development Center (ORDC) of the JAEA have used fixed 5-year meteorological statistics for derivation of atmospheric dispersion factors as average conditions. To show that the meteorological statistics for any 5-year period could be used as representative data for evaluation of average conditions, annual average (1-year average) and 5-year average of evaluated radionuclide concentrations derived from the meteorological data observed from 1991 to 2010 at ORDC were analyzed. The fluctuations of evaluated radionuclide concentrations of any 5-year averages were smaller than those of 1-year averages during 20 years, and any 5-year averages contained no rejections by the F-test (5% significance level). It means that any 5-year averages of radionuclide concentration evaluations are well representative for the safety analysis under normal condition in ORDC.
Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Numari, Hideyuki*; Sato, Naomitsu*; Nemoto, Koji*; Takasaki, Hiroichi*; Shimizu, Takehiko; Takasaki, Koji
JAEA-Data/Code 2013-006, 100 Pages, 2013/06
This report presents the results of emergency radiation monitoring, including ambient -ray dose rate, atmospheric radioactivity, meteorological observation and estimation of internal exposure resulting from the accident at the Fukushima Daiichi Nuclear Power Plant triggered by the earthquake off the pacific coast of Tohoku on 11th March 2011, conducted by Oarai Research and Development Center (ORDC), Japan Atomic Energy Agency (JAEA) from March to May, 2011. ORDC is located in the central part of Ibaraki prefecture and approximately 130 km southwest of the Fukushima Daiichi Nuclear Power Plant. From around 15th to 21st March, 2011, the ambient -ray dose rate increased and many radioactive nuclides were detected in the atmosphere.
Takashima, Hideki; Takasaki, Koji; Shimizu, Takehiko; Kurihara, Ryoichi
Genshiryoku eye, 57(5), p.72 - 76, 2011/05
no abstracts in English
Takeyasu, Masanori; Takeishi, Minoru; Shimizu, Takehiko; Iida, Takao*
Hoken Butsuri, 39(4), p.382 - 390, 2004/00
A computer code system was developed to evaluate a real-time environmental radiation dose when radioactive substances were accidentally released from a nuclear facility. The examination of the system was performed by using the data of air absorbed dose rate observed at monitoring stations and monitoring posts around the Tokai Reprocessing Plant when Kr was discharged during its normal operation.
Takeyasu, Masanori; Takeishi, Minoru; Nakano, Masanao; Shimizu, Takehiko
Saikuru Kiko Giho, (23), p.71 - 78, 2004/00
The computer system named SIERRA-II has been developed for calculating an environmental dose when unexpected releases of radioactivity happend from the nuclear facilities in the Tokai Works and Oarai Engineering Center. This report described the outline of SIERRA-Ii and the results of its performance exmanination by using the moniroting data under the normal operation of the Tokai Reprocessing Plant.
Hosotani, Risa; Sato, Naomitsu*; Shimizu, Takehiko; KOBAYASHI, Hideo
Saikuru Kiko Giho, (25), p.25 - 32, 2004/00
To observe the airborne gamma radiation dose rate, monitoring posts are set up to a border of supervised area of JNC-OEC. Measurement values of some ionization chambers set at monitoring posts were increased by unknown origin signal at random times. To probe the cause, measurement of electric field intensity at the ionization chamber and immunity test at anechoic chamber are carry out. Result of examination made clear that measurement values are increased by specific frequency band electromagnetic wave. They were also clearly that ferrite cores and shield tube are effective as eliminate of an electromagnetic wave noise. When ferrite cores are attached to cables of ionization chambers, unknown increase of measurement value doesn't occur.
Nakano, Masanao; Watanabe, Hitoshi; Shimizu, Takehiko; ; Morita, Shigemitsu; Katagiri, Hiromi
Journal of Radioanalytical and Nuclear Chemistry, 243(2), p.319 - 322, 2002/00
Times Cited Count:2 Percentile:19.45(Chemistry, Analytical)None
Koyama, Tomozo; ; ; Omori, Eiichi; ; ; Kitatani, Fumito; Kosugi, Kazumasa; Sudo, Toshiyuki; Kikuchi, Naoki; et al.
Nihon Genshiryoku Gakkai-Shi, 40(10), p.740 - 766, 1998/00
Times Cited Count:1 Percentile:15.05(Nuclear Science & Technology)None
Iwai, Makoto; Akutsu, Ken*; *; *; Shimizu, Takehiko*; Hayashi, Naomi*; *; Maruo, Yoshihiro
PNC TN852 84-06, 379 Pages, 1984/03
This manual includes the standard procedures for analysis of radioactive materials and chemical pollutants in liquid and gaseous waste effluent discharged into the environment from the nuclear facilities of Tokai Works of PNC. The second edition, PNCT852 - 79 - 10 was published in 1979. Almost all analytical procedures have been modified and new technique has been used for these five years, so the third edition revised entirely was to be published this time. The principal consideration was placed on the revision of sample preparation and safety handling of the chemical agents in particular.
Kitahara, Yoshihisa*; *; *; *; Shimizu, Takehiko*; Hayashi, Naomi*; *
PNC TN841 80-73, 45 Pages, 1980/12
no abstracts in English
Suzuki, Yutaka; Kuno, Takehiko; Nemoto, Hirokazu*; Okano, Masanori; Goto, Yuichi; Igarashi, Kazuto*; Shimizu, Yasuyuki; Suda, Shizuka; Yamada, Keiji; Watahiki, Masaru
no journal, ,
no abstracts in English
Haba, Risa; Yamada, Junya; Seya, Natsumi; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji
no journal, ,
no abstracts in English
Wada, Takeshi; Araake, Yuji; Ueda, Hisao; Takasaki, Koji; Shimizu, Takehiko; Ito, Kimio
no journal, ,
no abstracts in English
Seya, Natsumi; Yamada, Junya; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji; Nemoto, Koji*; Sato, Naomitsu*
no journal, ,
no abstracts in English
Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji
no journal, ,
no abstracts in English
Yamada, Junya; Seya, Natsumi; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji
no journal, ,
no abstracts in English