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JAEA Reports

Historical changes and Correspondence to Research and Test Reactors New Regulatory Standards for Monitoring Post in Oarai Research and Development Institute, JAEA

Hamaguchi, Takumi; Yamada, Junya; Komatsuzaki, Naoya*; Hatakeyama, Takumi; Seya, Natsumi; Muto, Yasunobu; Miyauchi, Hideaki; Hashimoto, Makoto

JAEA-Technology 2022-038, 65 Pages, 2023/03

JAEA-Technology-2022-038.pdf:4.3MB

New regulatory requirements were developed taking into account the lessons-learnt from the accident at Fukushima Daiichi Nuclear Power Station on March 2011. The new regulatory standards required that monitoring posts should be diversified in transmission systems and equipped with backup power supply equipment for design basis accidents. In this report, we look back on the history of monitoring posts in Oarai Research and Development Institute, explained the application for the permission of reactor installment license, application for approval of the design and construction method, pre-use operator's inspection and improvement design of monitoring posts. This report also includes about inspection based on act on special measures concerning nuclear emergency preparedness and the installation of KURAMA-II, which was carried out in conjunction with the improvement of monitoring post for new regulatory standards. As an appendix, application document for approval of the design and construction method are included.

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.

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.

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

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

Oral presentation

Regional contribution through the environmental monitoring which was conducted by JAEA Oarai, followed by the Fukushima Dai-ichi Nuclear Disaster

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

no journal, , 

no abstracts in English

Oral presentation

Determination of concentration of radioiodine in plume resulting from the accident at the FDNPP by analysis of pulse-height distributions observed at monitoring posts using the EGS code system

Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Shimizu, Takehiko; Takasaki, Koji; Yokoyama, Sumi*; Shimo, Michikuni*

no journal, , 

no abstracts in English

Oral presentation

Actual effect on the radiation dose rate caused by difference of the detector height above the ground in nuclear emergency monitoring

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

no journal, , 

no abstracts in English

Oral presentation

Study on estimation of I-131 concentrations in atmosphere using measured data by monitoring posts

Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Hashimoto, Makoto; Shimizu, Takehiko; Takasaki, Koji; Yokoyama, Sumi*; Shimo, Michikuni*

no journal, , 

no abstracts in English

Oral presentation

Comparison of I-131 concentrations in atmosphere estimated from pulse-height distribution observed by NaI(Tl) detector at monitoring posts and evaluated from air sampling

Yamada, Junya; Seya, Natsumi; Haba, Risa; Muto, Yasunobu; Hashimoto, Makoto; Shimizu, Takehiko; Takasaki, Koji; Yokoyama, Sumi*; Shimo, Michikuni*

no journal, , 

no abstracts in English

Oral presentation

Installation of KURAMA-II for on-site monitoring

Maeda, Eita; Hashimoto, Makoto; Nohara, Naofumi; Muto, Yasunobu; Yamada, Junya; Hamaguchi, Takumi; Inoue, Yuki

no journal, , 

no abstracts in English

Oral presentation

Long-term stationary monitoring data of KURAMA-II under the on-site environment

Igarashi, Yu; Hamaguchi, Takumi; Maeda, Eita; Yamada, Junya; Muto, Yasunobu; Tanigaki, Minoru*; Nohara, Naofumi

no journal, , 

At the JAEA Oarai Research Establishment, a portable KURAMA equipped with a data transmission function through an autonomous network using the ZETA standard was permanently installed near the MP for the purpose of redundancy in the measurement of monitoring points, and a system for observing radiation doses near the site boundary was developed. In this presentation, we report on the fixed point observation data for about one year using this system.

Oral presentation

Introduction of KURAMA-II with wireless communication "ZETA" for monitoring nuclear operators

Igarashi, Yu; Hamaguchi, Takumi; Maeda, Eita; Yamada, Junya; Muto, Yasunobu; Nohara, Naofumi

no journal, , 

At the Oarai Research Institute of the Japan Atomic Energy Agency, a portable KURAMA equipped with a data transmission function using an autonomous network based on the ZETA standard was permanently installed in the vicinity of the MP, and a system for observing radiation doses around the site boundary was developed. In this presentation, the background to the redundancy of post-measurement monitoring, which is the purpose of this system installation, and the fixed-point observation data for about one year will be reported.

16 (Records 1-16 displayed on this page)
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