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佐藤 優樹
Applied Radiation and Isotopes, 185, p.110254_1 - 110254_7, 2022/07
In a radiation environment, such as the decommissioning site of a nuclear power station, visualization of the distribution of radioactive substances and estimation of the dose equivalent rate around the site can help reduce the exposure dose of workers and plan their work. The author has developed a method of visualizing the existence of a radiation source using a gamma-ray imager, estimating its radioactivity, and estimating the dose equivalent rate around the source. A Compton camera, which is a gamma-ray imager, is used to visualize the existence of a 
Cs radiation source and estimate its radioactivity, and a three-dimensional (3D) model of the region around the source is generated using a simultaneous localization and mapping device based on 3D light detection and ranging. Next, the dose equivalent rate around the source is calculated by importing the 3D model data and radioactivity information into a particle and heavy ion transport code system code. The validity of the calculated dose equivalent rates was confirmed by comparing them with values measured using a survey meter. This method can be used not only to simply visualize a source and calculate the dose equivalent rate around it but also to evaluate how addition of shielding or removal of contaminated objects can contribute to reducing the dose equivalent rate.
佐藤 優樹
Physics Open (Internet), 7, p.100070_1 - 100070_8, 2021/05
To understand radiation information, such as dose rate and the position of radioactive substances in a radioactive working environment in detail, the author proposes the construction of a mirror world of the environment. In the proposed mirror world, the work environment is reproduced in a virtual space, and the radiation information measured in a real space is projected onto the virtual space. Note that in addition to displaying the radiation information in the virtual space, the visualization result of the radiation information in the virtual space is used for decision-making in the real space. It is seen that the radiation measurement in the real space and visualization of measurement results in the virtual space always interact. In this report, the author introduces an example of building the mirror world based on radiation measurements performed in a laboratory using Cs as a radiation source. In the laboratory, the dose rate was measured by using a survey meter together with a device for the simultaneous localization and mapping based on three-dimensional (3D) light detection and ranging. The measured dose rate was mapped onto the work environment in the virtual space. Technologies developed by the author, for example, the 3D visualization of the radiation source based on an integration of the Compton camera and structure-from-motion technology and the virtual-reality experience technology of the work environment that displays the source image were also used. The technology to project the radiation-source image into the real space using augmented-reality is also introduced in this report.
gamma-ray spectrometer suitable for the decommissioning of the Fukushima Daiichi Nuclear Power Station冠城 雅晃; 島添 健次*; 大鷹 豊*; 上ノ町 水紀*; 鎌田 圭*; Kim, K. J.*; 吉野 将生*; 庄子 育宏*; 吉川 彰*; 高橋 浩之*; et al.
Nuclear Instruments and Methods in Physics Research A, 971, p.164118_1 - 164118_8, 2020/08
被引用回数：7 パーセンタイル：65.65(Instruments & Instrumentation)Our work focused on the passive gamma-ray analysis (PGA) of the nuclear fuel debris based on measuring gamma rays with an energy greater than 1 MeV for the decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). The PGA requires gamma-ray spectrometers to be used under the high dose rates in the FDNPS, then we fabricated a small cubic CeBr spectrometer with dimensions of 5 mm 
5 mm 5 mm, coupled to a Hamamatsu R7600U-200 photomultiplier tube (PMT). The performance at dose rates of 4.4 to 750 mSv/h in a 
Co field was investigated. The energy resolution (FWHM) at 1333 keV ranged from 3.79% to 4.01%, with a standard deviation of 6.9%, which met the narrow gamma decay spectral lines between 
Eu (1274 keV) and Co (1333 keV). However, the spectra shifted to a higher energy level as the dose rate increase, there was a 51% increase at the dose rates of 4.4 to 750 mSv/h, which was caused by the PMT gain increase.
伊勢 武治; 丸尾 毅; 宮坂 靖彦; 一色 正彦; 谷 政則; 石仙 繁; 宮本 啓二; 成田 秀雄*
JAERI-M 85-050, 117 Pages, 1985/04
JRR-3改造炉の設計のための遮断解析を実施した。遮断設計の基本方針、遮断解析の方法及び遮断解析の結果が述べられている。原子炉本体の遮断、カナルの遮断、使用済燃料プールの遮断などについて述べてある。
線量率の評価,2橋倉 宏行*; 斎藤 伸三; 岡 芳明*; 柳沢 一郎*; 大友 正一
JAERI-M 9142, 49 Pages, 1980/10
NSRRの実験孔内に実験用カプセル及びアルミニウム減速層を挿入した場合の実験孔内の中性子束及びガンマ線量率分布を測定した。ニ次元輸送計算コードTWOTRAN-IIによりこれらの値を計算により求め相互比較した。実験孔内に実験用カプセルを挿入した場合、無挿入の場合と比較して中性子束は約1/10、線量率は1/2~1/3低くなり、アルミニウム減速層の場合には中性子束線量率とも1/4~1/5の低下であった。また、二次元輸送計算の結果、実験孔内がポイドの場合は中性子反応率、線量率とも場所によっては実験値と100%以上異なるが、アルミニウム減速層挿入の場合には約50%の誤差の範囲内で両者は一致した。
-ray dose rates from a Co cylindrical source with shell-shaped shields金森 信彦*; 古田 悠
Nuclear Science and Engineering, 36(2), p.238 - 245, 1969/00
None
Co cylindrical source古田 悠; 金森 善彦
J.Nucl.Sci.Engng., 30, p.261 - 267, 1967/00
被引用回数：2抄録なし
団野 皓文*; 矢作 吉之助*
Journal of Applied Physics, 34(4), p.804 - 809, 1963/00
被引用回数：30抄録なし
-ray dose rates on the upper core structure of the experimental fast reactor Joyo伊藤 主税; 山本 崇裕; 前田 茂貴; 伊東 秀明; 関根 隆
no journal, ,
高速実験炉「常陽」で行われた旧炉心上部機構(UCS)収納キャスクの遮蔽設計と引き抜き作業の放射線管理に資するため、QADコードによる計算値を炉内の線量率測定結果により補正して、旧UCSの線量率を評価した。この評価手法を検証するため、プラスチックシンチレーション光ファイバ(PSF)を用いて、旧UCSが収納された状態のキャスク表面の線強度分布を測定した。一方、前述の評価手法によりキャスク表面の線量率を計算し、PSFの検出器応答を求めてPSFによる測定値と比較した。その結果、計算値は測定値の2倍程度で位置分布の傾向は一致した。計算値と測定値の比を用いて計算値を修正した最終評価値は、サーベイメータによる何点かの測定値とおおむね一致し、線評価手法の妥当性を確認した。
