Radiation imaging of a highly contaminated filter train inside Fukushima Daiichi Nuclear Power Station Unit 2 using an integrated Radiation Imaging System based on a Compton camera

Sato, Yuki; Terasaka, Yuta

Journal of Nuclear Science and Technology, 60(8), p.1013 - 1026, 2023/08

https://doi.org/10.1080/00223131.2022.2159894

Guidance for gamma spectrometry intercomparison based on the information obtained through five intercomparisons during the Fukushima mapping project

Mikami, Satoshi; Ishikawa, Daisuke*; Matsuda, Hideo*; Hoshide, Yoshifumi*; Okuda, Naotoshi*; Sakamoto, Ryuichi*; Saito, Kimiaki

Journal of Environmental Radioactivity, 210, p.105938_1 - 105938_7, 2019/12

https://doi.org/10.1016/j.jenvrad.2019.03.014

Five intercomparisons of in situ spectrometry by 6-7 participating teams have been conducted between December 2011 and August 2015 at sites in Fukushima prefecture which affected by the fallout of FDNPS accident occurred in March 2011. The evaluated deposition densities agreed within 5-6% in terms of coefficient of variation (CV) for radiocesium (Cs and Cs), by our best achievement, and the ratio of Cs/Cs in deposition density agreed within 1-2% in CV, through five intercomparisons. These results guarantee the accuracy of the measurements of the mapping project. Two different methods for intercomparison were conducted: (1) sequential measurements at an identical point; and (2) simultaneous measurements in a narrow area within 3 m radius. In a comparison between the two methods at a site, no significant difference was observed between the results. The standard protocols for the two different intercomparison methods were proposed based on our experience.

Dosimetry for 3-45 MeV/u ion beams using thin film dosimeters

Kojima, Takuji; Sunaga, Hiromi; Takizawa, Haruki; Hanaya, Hiroaki; Tachibana, Hiroyuki*

JAERI-Review 2002-035, TIARA Annual Report 2001, p.123 - 124, 2002/11

Thin film dosimeters of about 10-200 mm in thickness, which were well -characterized for Co -rays or 2-MeV electrons, have been applied to dosimetry for ion beams. For development of dosimetry covering the dose range of 0.005 to 200 kGy with high precision within 5%, the linear energy transfer (LET) characteristics of thin films were studied involving development of precise fluence measurement. Dose mapping technique was also developed achieving high spatial resolution values of about 1m and 10m for lateral and depth directions respectively. The outline of the recent development is summarized in this paper.

ETC-Rel code; Orbit trace code of relativistic electrons in a tokamak

Tokuda, Shinji; *

JAERI-Data/Code 98-032, 36 Pages, 1998/11

JAERI-Data-Code-98-032.pdf:1.93MB

no abstracts in English

Stability Analyses of Tokamak Plasmas by Computer Simulation

JAERI-M 84-040, 90 Pages, 1984/03

JAERI-M-84-040.pdf:2.28MB

no abstracts in English

Sensor database for research of SLAM in reactor buildings

Yamada, Taichi; Kawabata, Kuniaki

no journal, , 

In reactor buildings of Fukushima Daiichi, there are still uninvestigated areas due to the accident on 11th March. Hence the reconnaissance by using remotely operated robot in reactor buildings is important for planning the decommissioning. Therefore, Simultaneous Localization And Mapping (SLAM) is a key technology in robotics. This research aims to construct the sensor database for the SLAM research base.

Bayesian hierarchical methods for spatiotemporal integration of radiation air dose rates

Murakami, Haruko*; Sun, D.*; Seki, Akiyuki; Takemiya, Hiroshi; Saito, Kimiaki

no journal, , 

This study presents a Bayesian hierarchical method to integrate multiple types of radiation measurements and to estimate the spatiotemporal distribution of radiation air dose rates around the Fukushima Daiichi Nuclear Power Plant. The method incorporates the temporal evolution of dose rates by separating the log-linear decay trend and the fluctuations of air dose rates which are spatially correlated based on adjacent monitoring post data.