Decontamination simulation and future prediction of air dose rate in difficult to return zone in Fukushima Prefecture

Yamashita, Takuya; Sawada, Noriyoshi*

JAEA-Research 2019-010, 227 Pages, 2020/03

JAEA-Research-2019-010.pdf:21.44MB
JAEA-Research-2019-010(errata).pdf:0.5MB

In order to support the decontamination activities proceeded by the national government and municipalities in terms of technology, we have developed a simulation system "RESET" which predicts the effect of decontamination. We also developed a "two-component model" for the purpose of predicting long-term changes in the air dose rate. We use these tools to perform decontamination simulation and predictive analysis of the air dose rate after decontamination, and provide information to the national government and municipalities aiming for reconstruction. In this report, the verification result of the prediction methods implemented using actual measurement data obtained in the "Decontamination model demonstration project in difficult-to-return zone" and "Survey result on transition of air dose rate after decontamination model demonstration project" conducted by Ministry of the Environment. In addition, the decontamination simulation conducted for the entire difficult-to-return area and the results of future prediction of the air dose rate after decontamination are shown.

Development, improvement and performance test of the groundwater monitoring system

Nanjo, Isao; Mizuno, Takashi; Murakami, Hiroaki; Amano, Yuki; Hosoya, Shinichi*; Wakahama, Hiroshi*; Yamashita, Riyo*

no journal, , 

This study aimed to develop a hydrochemical monitoring system for in-situ groundwater. JAEA has developed the hydrochemical monitoring system which is available at underground facility focused on low-permeable sedimentary rocks. After performance test, it can be demonstrated that the monitoring system is workable completely at 350m depth research gallery.

Solute transport / retardation study in the Mizunami Underground Research Laboratory Project; Through diffusion experiment using rock samples

Yamashita, Riyo; Hama, Katsuhiro; Morikawa, Keita*; Hosoya, Shinichi*

no journal, , 

no abstracts in English

Sample preparation procedure for ESR dosimetry using teeth of wild animal

Oka, Toshitaka; Mitsuyasu, Yusuke*; Takahashi, Atsushi*; Koarai, Kazuma; Kino, Yasushi*; Sekine, Tsutomu*; Okutsu, Kenichi*; Yamashita, Takuma*; Shimizu, Yoshinaka*; Chiba, Mirei*; et al.

no journal, , 

Releases of the radioactive materials from the Fukushima Daiichi Nuclear Power Plant accident result in a low dose exposure to wild animals. The external dose of wild animals is commonly estimated by the external dose rate of the captured point, but the estimated exposure dose has huge uncertainties because the size of the habitat and/or the movement of the wild animals are not included in the estimation. To estimate the external dose precisely, we utilize electron spin resonance (ESR) dosimetry. In this work, we investigated the sample preparation procedure of wild animals. The ESR spectrum of enamel of racoon captured in Namie-town, Fukushima has a broad ESR signal due to metal components. The linear relationship between the Co intensity and the absorbed dose that we can apply ESR dosimetry for racoon teeth. Using this relationship, the external exposure dose was estimated.