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Journal Articles

Improvement of estimation of $$^{131}$$I concentrations in the air using data measured by monitoring posts applied by determination of passing-through time of plume using noble gas counts

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 $$^{131}$$I concentrations in the air using data measured by monitoring posts in case that a nuclear disaster occurs. In this method, $$^{131}$$I concentrations were estimated by multiplying $$^{131}$$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 $$^{131}$$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 $$^{131}$$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 $$^{131}$$I concentrations in the air were within factor 3.

Journal Articles

Calculation of conversion factor for estimation of $$^{131}$$I concentrations in the air from pulse-height distribution observed by NaI(Tl) detector in monitoring posts

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 $$^{131}$$I concentrations in the air using data measured by monitoring posts. In this method, $$^{131}$$I concentrations were estimated by multiplying $$^{131}$$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$$^{3}$$/cps.

Journal Articles

2016 Professional Engineer (PE) test preparation course "Nuclear and Radiation Technical Disciplines"

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

Journal Articles

Applicability of meteorological statistics over a 5-year period to evaluation of annual average of radionuclide concentration in surface air; Based on meteorological statistics for 20 years at Oarai Research and Development Center, JAEA

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.

JAEA Reports

Environmental radiation monitoring resulting from the accident at the Fukushima Daiichi Nuclear Power Plant, conducted by Oarai Research and Development Center, JAEA; Results of ambient gamma-ray dose rate, atmospheric radioactivity and meteorological observation

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

JAEA-Data-Code-2013-006.pdf:12.04MB

This report presents the results of emergency radiation monitoring, including ambient $$gamma$$-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 $$gamma$$-ray dose rate increased and many radioactive nuclides were detected in the atmosphere.

Journal Articles

Journal Articles

Development of a Real-Time Environmental Radiation Dose Evaluation System for the Vicinity of a Nuclear Facility; A Study of a Real-Time Environmental Radiation Dose Evaluation System

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 $$^{85}$$Kr was discharged during its normal operation.

Journal Articles

Development of Simulation System (II) for Emergency Dose by Released Radioactive Substances (SIERRA-II)

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.

Journal Articles

Countermeasure of Electromagnetic Wave Noise at Ionization Chamber Used Monitoring Posts

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.

Journal Articles

Environmental Radiation Monitoring after the Accidental Release from Bituminization Demonstration Facility

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:20.05(Chemistry, Analytical)

None

JAEA Reports

None

Noda, Kimio; Shimizu, Takehiko; Ishiguro, Hideharu

PNC TN8420 98-018, 165 Pages, 1998/03

PNC-TN8420-98-018.pdf:11.85MB

None

Journal Articles

The Fire and Explosion Incident at Bituminization Demonstration Facility of PNC Tokai Works

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:15.58(Nuclear Science & Technology)

None

JAEA Reports

Manual of standard procedures for analysis of radioactive effluents and gases discharged into environment

Iwai, Makoto; *; *; *; Shimizu, Takehiko*; Hayashi, Naomi*; *; Maruo, Yoshihiro

PNC TN852 84-06, 379 Pages, 1984/03

PNC-TN852-84-06.pdf:11.08MB

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.

JAEA Reports

None

Kitahara, Yoshihisa*; *; *; *; Shimizu, Takehiko*; Hayashi, Naomi*; *

PNC TN841 80-73, 45 Pages, 1980/12

PNC-TN841-80-73.pdf:2.06MB

no abstracts in English

Oral presentation

MOX reprocessing at TRP, 8; Development of hull monitor for MOX spent fuel, 1; Determination of plutonium, curium and uranium in hull pieces by destructive analysis

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

Oral presentation

Consideration of the rising count rate of the water monitor at rainfall time

Haba, Risa; Yamada, Junya; Seya, Natsumi; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji

no journal, , 

no abstracts in English

Oral presentation

On the field measurement of glass dosimeter compering with TLD batch

Wada, Takeshi; Araake, Yuji; Ueda, Hisao; Takasaki, Koji; Shimizu, Takehiko; Ito, Kimio

no journal, , 

no abstracts in English

Oral presentation

Relation between a defference of an air diffusion for the year and a meteorological observation period at O-arai Centre, JAEA

Seya, Natsumi; Yamada, Junya; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji; Nemoto, Koji*; Sato, Naomitsu*

no journal, , 

no abstracts in English

Oral presentation

Environmental radiation monitoring in JAEA O-arai after Fukushima Daiichi NPP accident; Measuring results of monitoring post

Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji

no journal, , 

no abstracts in English

Oral presentation

Environmental radiation monitoring in JAEA O-arai after Fukushima Dai-ichi NPP accident; Estimation of radionuclide concentrations using Monte Carlo simulation

Yamada, Junya; Seya, Natsumi; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji

no journal, , 

no abstracts in English

26 (Records 1-20 displayed on this page)