検索対象:     
報告書番号:
※ 半角英数字
 年 ~ 
 年
検索結果: 244 件中 1件目~20件目を表示

発表形式

Initialising ...

選択項目を絞り込む

掲載資料名

Initialising ...

発表会議名

Initialising ...

筆頭著者名

Initialising ...

キーワード

Initialising ...

使用言語

Initialising ...

発行年

Initialising ...

開催年

Initialising ...

選択した検索結果をダウンロード

論文

Development of a Gd$$_{2}$$Si$$_{2}$$O$$_{7}$$ (GPS) scintillator-based alpha imaging detector for rapid plutonium detection in high-radon environments

森下 祐樹; 井崎 賢二; 金子 純一*; 山本 誠一*; 樋口 幹雄*; 鳥居 建男

IEEE Transactions on Nuclear Science, 67(10), p.2203 - 2208, 2020/10

Gd$$_{2}$$Si$$_{2}$$O$$_{7}$$(GPS)シンチレータベースの$$alpha$$線イメージング検出器を開発し、実際のプルトニウム(Pu)粒子と$$^{222}$$Rn子孫核種を測定することにより、$$^{222}$$Rn子孫核種存在下でのPu粒子検知の有効性を実証した。GPSシンチレータプレートの外形寸法は5$$times$$5cmで、シンチレータ層は厚さ3mmの高透明ガラス上に構成され、シンチレータ層の厚みは約50ミクロンであった。シンチレータプレートは、位置感知型光電子増倍管にシリコーングリースで光学的に結合した。開発した$$alpha$$線イメージング検出器は良好な感度の均一性を示した。Pu粒子の放射能を検出器上の14か所の異なる位置で評価した。測定した$$alpha$$線のカウントから放射能は正確に評価され、その差異は$$pm$$6%以内となった。Pu同位体の$$alpha$$線エネルギー領域にエネルギーウィンドウを適用することにより、ラドン222子孫核種のカウントを65.3%減少することができた。Pu/$$^{222}$$Rn子孫放射能比は1/51であったが、Pu粒子は5分測定で$$^{222}$$Rn子孫核種から識別された。したがって、開発した$$alpha$$線イメージング検出器は、高いラドンバックグラウンド環境下でのでのPu粒子の汚染のモニタリングに有効である。

論文

Construction of virtual reality system for radiation working environment reproduced by gamma-ray imagers combined with SLAM technologies

佐藤 優樹; 峯本 浩二郎*; 根本 誠*; 鳥居 建男

Nuclear Instruments and Methods in Physics Research A, 976, p.164286_1 - 164286_6, 2020/10

 被引用回数:0 パーセンタイル:100(Instruments & Instrumentation)

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., experienced a meltdown as a result of a large tsunami caused by the Great East Japan Earthquake on March 11, 2011. At that time, it was necessary to understand the aspects of the decommissioning working environment inside the FDNPS, such as establishing how the radioactive substances were distributed across the site, for work to be done efficiently without exposure to large amounts of radiation. Therefore, virtual reality (VR) emerged as a solution. There have been previous reports done on a technique for visualizing the distribution of radioactive substances in three dimensions utilizing a freely moving gamma-ray imager combined with simultaneous localization and mapping (SLAM) technology. In this paper, we introduce imaging technologies for the acquisition of image data from radioactive substances and three-dimensional (3D) structural models of the working environment, using a freely moving gamma-ray imager combined with SLAM technology. For this research, we also constructed a VR system and displayed the 3D data in a VR space, which enables users to experience the actual working environment without radiation exposure. In creating the VR system, any user can implement this method by donning an inexpensive head-mounted display apparatus and using a free, or low-cost, application software.

論文

A Cubic CeBr$$_{3}$$ 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:0 パーセンタイル:100(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$$_{3}$$ spectrometer with dimensions of 5 mm $$times$$ 5 mm $$times$$ 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 $$^{60}$$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 $$^{154}$$Eu (1274 keV) and $$^{60}$$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.

論文

Retracted article; Visualization and integration of images of radioactive substances as point cloud data in 3-D environment models

佐藤 優樹; 鳥居 建男

Nuclear Technology, 206(7), p.v - xvi, 2020/07

 被引用回数:1 パーセンタイル:21.8(Nuclear Science & Technology)

The Fukushima Daiichi Nuclear Power Station (FDNPS) suffered a meltdown as a result of a large tsunami triggered by the Great East Japan Earthquake on March 11, 2011. Understanding the distribution of radioactive substances inside the FDNPS is essential to execute appropriate decommissioning tasks. In this paper, we propose method for visualizing three-dimensional (3D) images of radioactive substances as a point cloud data (PCD) and integrating these data into 3D environment models. To demonstrate the usefulness of the proposed methods, a Compton camera was first employed to capture 3D images of radiation sources. The resulting PCD were then integrated into a 3D environment model of a measurement area acquired using the 3D light detection and ranging (LiDAR). This allowed in successful construction of a map to visually recognize the positions of radiation sources.

論文

Statement of retraction; Visualization and integration of images of radioactive substances as point cloud data in 3-D environment models

佐藤 優樹; 鳥居 建男

Nuclear Technology, 206(7), P. 1095, 2020/07

 被引用回数:0 パーセンタイル:100(Nuclear Science & Technology)

The authors have requested the retraction of their article due to an identified defect in the Compton camera software, which resulted in an incorrect output value for the interaction position of the gamma rays in the sensor of the camera. It is expected that the experimental results may not change significantly with the bug correction; however, many figures would need to be replaced. The authors may seek a separate publication of an updated manuscript in the future.

論文

Remote detection of radioactive hotspot using a Compton camera mounted on a moving multi-copter drone above a contaminated area in Fukushima

佐藤 優樹; 小澤 慎吾*; 寺阪 祐太; 峯本 浩二郎*; 田村 智志*; 新宮 一駿*; 根本 誠*; 鳥居 建男

Journal of Nuclear Science and Technology, 57(6), p.734 - 744, 2020/06

 被引用回数:1 パーセンタイル:21.8(Nuclear Science & Technology)

The Fukushima Daiichi Nuclear Power Station, operated by Tokyo Electric Power Company Holdings, Inc., suffered a meltdown as a result of a large tsunami triggered by the Great East Japan Earthquake on March 11, 2011. To proceed with the environmental recovery by decontamination, drawing a radiation distribution map that can indicate the distribution of radioactive substances is extremely important to establish detailed decontamination plans. We developed a remote radiation imaging system consisting of a lightweight Compton camera and a multi-copter drone to remotely measure the distribution of the radioactive substances. This system can perform radiation imaging using a Compton camera while flying and moving. In addition, it is also possible to draw the distribution of radioactive substances three-dimensionally by projecting the radiation image measured with the Compton camera on a three-dimensional topography model separately acquired by a 3D-LiDAR. We conducted a survey of radioactive hotspots in difficult-to-return zone in the coastal area of Fukushima, Japan. The drone system succeeded in three-dimensional visualization of several hotspots deposited on the ground. Such remote technology would be useful not only for monitoring the difficult-to-return zone, but also for monitoring distribution of radioactive substances inside the site of the FDNPS where decommissioning work is ongoing.

論文

Evaluation of an ultra-thin plastic scintillator to detect alpha and beta particle contamination

森下 祐樹; 星 勝也; 鳥居 建男

Nuclear Instruments and Methods in Physics Research A, 966, p.163795_1 - 163795_8, 2020/06

これまでに、福島第一原子力発電所(FDNPS)の原子炉建屋でアルファおよび高$$beta$$粒子エミッターが検出された。FDNPS原子炉建屋の$$beta$$放射線レベルは非常に高いため、ガイガーミュラー(GM)カウンターなどの市販のベータ測量計では、$$beta$$汚染レベルを測定できない。この問題を解決するために、極薄のプラスチックシンチレータを使用して、アルファおよびベータ汚染の検出器を開発した。検出器の評価のため、7, 22, 24, 31, 39、および55$$mu$$mのさまざまな厚さの超薄型プラスチックシンチレータを準備した。それらの感度をテストするために、各シンチレータをガラスプレートと2インチの位置に敏感な光電子増倍管に光学的に結合し、アルファ, ベータ、またはガンマ線源に曝露した。アルファ分光法の結果は、厚さ55$$mu$$mのプラスチックシンチレータのみがアルファ粒子(5.5MeV)を完全に吸収し、半値全幅が16.7%であった。高ベータバックグラウンド下でのアルファイメージングの場合、厚さ7$$mu$$mのプラスチックシンチレータが最良の選択であり、アルファ対ベータ比が652であることがわかった。また、厚さ7$$mu$$mのプラスチックシンチレータは1MBq $$^{90}$$Sr/$$^{90}$$Y線源に直接コンタクトして測定しても41.74$$pm$$0.93cpsのカウントレートであり、非常に低感度であるため飽和せずに測定を行うことが可能である。したがって、厚さ7$$mu$$mのプラスチックシンチレータを使用して、以前の方法では不可能だったFDNPSサイトのベータの表面汚染レベルをリアルタイムで直接測定することができる。

論文

Development of one-dimensional optical fiber type radiation distribution sensing method based on wavelength spectrum unfolding

寺阪 祐太; 渡辺 賢一*; 瓜谷 章*; 山崎 淳*; 佐藤 優樹; 鳥居 建男; 若井田 育夫

Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05

For the application in the measurement of the high dose rate hot spots inside the Fukushima Daiichi Nuclear Power Station buildings, we propose a wavelength-resolved type one-dimensional radiation distribution sensing method using plastic scintillating fiber (PSF). The proposing method estimates the incident position of radiation to the PSF by the unfolding of the wavelength spectrum output from the fiber edge using the fact that the attenuation length of scintillating light depends on the wavelength. By measuring the response function in advance, which defined as the wavelength spectrum measured at the fiber edge by the spectrometer with every transmission distance, the spectrum which can obtain when measured a certain radiation distribution can be expressed as the convolution of the response function. This method can avoid the problem of chance coincidence effect and signal pile-up, which occurs in the radiation detector with pulse counting mode under high dose rate field because this method measures the integrated light intensity. Through basic experiment using the ultraviolet irradiation source and $$^{90}$$Sr point source, basic properties of inverse estimation of irradiated position were confirmed, which showed that source position was reasonably estimated using the response function which obtained by the ultraviolet irradiation source in advance.

論文

A Study of directional gamma-ray detector without shield by Monte Carlo simulation

北山 佳治; 寺阪 祐太; 佐藤 優樹; 鳥居 建男

Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05

At the Fukushima Daiichi Nuclear Power Station (FDNPS), various works are under-way for decommissioning. Depending on work places, there are radioactive hotspot. Therefore measuring the position of the hotspot in advance is important for safety of the worker. The system that can easily measure the dose rate distribution in work place has been demanded. There are two methods for imaging a dose rate distribution: a pinhole camera and a Compton camera. A pinhole camera can determine direction of radiation source in one event, but the weight becomes heavy because a shield is required. On the other hand, since the Compton camera does not require a shield, it can be reduced in the size and weight. However, Compton imaging method generate many ghosts of cone traces, which reduce the signal-to-noise ratio. We propose a new gamma-ray imager that works like a pinhole camera without a shield. This is achieved by arranging directional gamma ray detectors that does not require a shield. In this work, we have performed principle verification of a directional gamma-ray detector that is a basic component of the new gamma-ray imager by using Geant4 Monte Carlo simulation.

論文

Visualization of radioactive substances using freely moving gamma-ray imager based on Structure from Motion

佐藤 優樹; 鳥居 建男

Proceedings of International Youth Nuclear Congress 2020 (IYNC 2020) (Internet), 4 Pages, 2020/05

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., suffered a meltdown as a result of a large tsunami triggered by the Great East Japan Earthquake on March 11, 2011. We have been conducting demonstration tests for detection of radioactive hotspots inside the FDNPS buildings using a Compton camera, a kind of gamma-ray imager. In this work, we introduced the 3D visualization of radioactive substances by using combination of the Compton camera and optical camera based on Structure from Motion (SfM). By taking photographs of the experimental environment while freely moving, a 3D structural model of the environment can be reconstructed from the multiple photographs, and the movement trajectory of the optical camera can be estimated simultaneously using the SfM. Furthermore, the radioactive substances can be visualized by drawing an image of the radioactive substances on the 3D structural model using gamma-ray data acquired by the Compton camera. In the demonstration, we succeeded in visualizing a $$^{137}$$Cs-radiation source on the 3D structural model of the experimental environment while freely moving these devices. This technology is useful for making it easy to recognize radioactive substances in decommissioning work site such as the FDNPS.

論文

A Remote continuous air monitoring system for measuring airborne alpha contamination

森下 祐樹; 宇佐美 博士; 古田 禄大; 青木 克憲; 鶴留 浩二; 星 勝也; 鳥居 建男

Radiation Protection Dosimetry, 189(2), p.172 - 181, 2020/04

遠隔$$alpha$$ダストモニタリング装置(RCAM)システムを開発した。RCAMシステムは、パーソナル$$alpha$$ダストモニターとロボットで構成した。パーソナル$$alpha$$ダストモニター(poCAMon, SARAD、ドイツ)は、400mm$$^{2}$$のイオン注入シリコン検出器と25mm$$phi$$のメンブレンエアフィルターで構成された。パーソナル$$alpha$$ダストモニターは、任意の測定時間間隔のアルファエネルギースペクトルを取得することが可能であった。実証測定は、瑞浪超深地層研究所(MIU)および換気の悪いコンクリートの建物で地下で行われた。RCAMシステムは遠隔操作され、相対湿度(RH)がほぼ100%であっても$$^{222}$$Rn子孫を正常に測定した。測定されたアルファスペクトルでは、$$^{218}$$Po(6.0MeVアルファ線)および$$^{214}$$Po(7.7MeVアルファ線)のピークが明確に識別された。我々の開発したモニターは、高ガンマ線環境または作業者が物理的に立ち入ることができない汚染場でのアルファダストモニタリングに有用である。

報告書

RADREMOTE 2018; Proceedings of The 5th Fukushima Research Conference (FRC) 2018; Radiation hardness, smartness and measurement in remote technology for the decommissioning of the Fukushima Daiichi Nuclear Power Station

冠城 雅晃; 鳥居 建男; 小川 徹

JAEA-Review 2019-031, 251 Pages, 2020/01

JAEA-Review-2019-031.pdf:57.36MB

福島第一原子力発電所の廃炉をはじめとした過酷な放射線環境下で、現場作業者の被ばく線量を低減するため、遠隔技術やロボティクスの高度化に大きな期待が集まっている。しかし、ロボットの遠隔制御のための最先端の要素技術やセンサー, 電子機器の耐放射線性にも厳しい限界がある。原子力へのロボット技術の応用拡大に向けて、機器の耐放射線性の向上(Radiation hardness)や運用における放射線環境への適応力(Radiation smartness)が求められる。さらに、将来の核燃料デブリの探査と取り出しに向けては、福島第一原子力発電所内の高線量率現場での放射線イメージングや核燃料デブリの検出といった、放射線計測(Radiation measurement)および位置認識・周辺環境の把握のための技術の開発が必要である。今回の福島リサーチカンファレンスでは、遠隔技術のさらなる進展のため、さまざまな分野の専門化を交えて将来のビジョンを共有することを目指している。

論文

$$alpha$$核種可視化検出器を用いた福島第一原子力発電所の核燃料起因$$alpha$$核種の検知

森下 祐樹; 宇佐美 博士; 鳥居 建男

Isotope News, (765), p.10 - 13, 2019/10

本論文は、福島第一原子力発電所の核燃料由来$$alpha$$核種の測定のため、$$alpha$$核種可視化検出器の開発と実際のスミヤ試料の測定について報告した。

論文

Radiation imaging using a compact Compton camera mounted on a crawler robot inside reactor buildings of Fukushima Daiichi Nuclear Power Station

佐藤 優樹; 寺阪 祐太; 宇津木 弥*; 菊地 弘幸*; 清岡 英男*; 鳥居 建男

Journal of Nuclear Science and Technology, 56(9-10), p.801 - 808, 2019/09

 被引用回数:4 パーセンタイル:18.47(Nuclear Science & Technology)

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown in the aftermath of a large tsunami caused by the Great East Japan Earthquake of 11 March 2011. Measurement of radiation distribution inside the FDNPS buildings is indispensable to execute decommissioning tasks in the reactor buildings. We conducted a radiation imaging experiment inside the reactor building of Unit 1 of FDNPS by using a compact Compton camera mounted on a crawler robot and remotely visualized gamma-rays streaming from deep inside the reactor building. Moreover, we drew a radiation image obtained using the Compton camera onto the three-dimensional (3-D) structural model of the experimental environment created using photogrammetry. In addition, the 3-D model of the real working environment, including the radiation image, was imported into the virtual space of the virtual reality system. These visualization techniques help workers recognize radioactive contamination easily and decrease their own exposure to radiation because the contamination cannot be observed with the naked eye.

論文

Development of an alpha dust monitor using a GPS scintillator plate

森下 祐樹; 金子 純一*; 樋口 幹雄*; 井崎 賢二; 矢島 辰雄*; 松浦 貢*; 田村 健; 鳥居 建男

Radiation Measurements, 122, p.115 - 120, 2019/03

 被引用回数:1 パーセンタイル:56.06(Nuclear Science & Technology)

A dust monitor with a silicon surface barrier detector (SSBD) is introduced at a nuclear fuel facility to detect airborne contamination of $$^{238}$$Pu and $$^{239}$$Pu released by past accidents. However, an SSBD frequently produces false alarms, especially in a room with high humidity. We developed an alpha-particle spectrometer based on a cerium-doped Gd$$_{2}$$Si$$_{2}$$O$$_{7}$$ (GPS) scintillator plate and a photomultiplier tube (PMT). The energy resolution for 5.5-MeV alpha particles was $$sim$$11.9% $$pm$$ 0.2% of the FWHM. The efficiency was 92%, and it had a uniform sensitivity. By applying an energy window, the count-rate of the Rn progeny decreased by 77%. The GPS scintillator plate was able to measure the alpha spectrum even though the GPS scintillator got wet.

論文

Detection of alpha particle emitters originating from nuclear fuel inside reactor building of Fukushima Daiichi Nuclear Power Plant

森下 祐樹; 鳥居 建男; 宇佐美 博士; 菊地 弘幸*; 宇津木 弥*; 高平 史郎*

Scientific Reports (Internet), 9, p.581_1 - 581_14, 2019/01

 被引用回数:3 パーセンタイル:18.47(Multidisciplinary Sciences)

We measured alpha emitters obtained from a reactor building in the Fukushima Daiichi Nuclear Power Plant (FDNPP) by using an alpha particle imaging detector. For developing the detector, we used a verythin (0.05-mm-thick) a cerium-doped Gd$$_{3}$$(Ga,Al)$$_{5}$$O$$_{12}$$ (Ce:GAGG) scintillator and silicon photomultiplier (SiPM) arrays as the photodetector. The floor of the reactor building in FDNPP was wiped off by using smear papers, and the radioactivity of these papers was measured by the alpha particle imaging detector. The alpha spectrum was in the energy range of 5-6 MeV, which corresponds to the alpha particle energy of $$^{238}$$Pu (5.5 MeV). Moreover, the peak of $$^{241}$$Am was identified by gamma spectrum measurement. Based on these results, we report actual findings of alpha emitters in the FDNPP reactor buildings originating from nuclear fuels.

論文

Evaluation of ecological half-life of dose rate based on airborne radiation monitoring following the Fukushima Dai-ichi Nuclear Power Plant accident

眞田 幸尚; 卜部 嘉*; 佐々木 美雪; 越智 康太郎; 鳥居 建男

Journal of Environmental Radioactivity, 192, p.417 - 425, 2018/12

 被引用回数:9 パーセンタイル:34.25(Environmental Sciences)

Many time of the airborne radiation monitoring was conducted. Temporal change of dose rate was evaluated based on airborne radiation monitoring. The air dose rate 5.6 years after the FDNPS accident has decreased by 80%. The increasing attenuation by radioactive cesium penetration into the soil was effective.

論文

Image reconstruction of radioactive contamination due to the Fukushima-Daiichi Nuclear Power Station Accident using a compact Compton camera

佐藤 優樹; 寺阪 祐太; 宮村 浩子; 冠城 雅晃; 谷藤 祐太; 川端 邦明; 鳥居 建男

Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.428 - 436, 2018/11

 被引用回数:0 パーセンタイル:100

We developed a lightweight compact Compton camera to measure the distribution of radioactive contamination inside the Fukushima Daiichi Nuclear Power Station. We conducted performance evaluation tests in the coastal area of Fukushima, Japan, using the camera, which employs a cerium (Ce)-doped GAGG (Gd$$_{3}$$Al$$_{2}$$Ga$$_{3}$$O$$_{12}$$) scintillator coupled with a multipixel photon counter. The camera can clearly visualize spreading of radioactivity along the ground surface. In addition, we performed three-dimensional image reconstruction of the distribution of radioactive contamination using the multi-angle data obtained with the Compton camera. We succeeded in obtaining a three-dimensional image of radioactive contamination in the outdoor area.

論文

Gamma-ray imaging system for Fukushima Daiichi Nuclear Power Plant using silicon strip detector

冠城 雅晃; 佐藤 優樹; 吉原 有里*; 島添 健次*; 高橋 浩之*; 鳥居 建男

Reactor Dosimetry; 16th International Symposium on Reactor Dosimetry (ISRD-16) (ASTM STP 1608), p.405 - 414, 2018/11

 被引用回数:0 パーセンタイル:100

On March 11, 2011, a massive earthquake occurred in the Tohoku region of Japan, and a large tsunami hit the Fukushima Daiichi Nuclear Power Plant (1F), resulting in a nuclear accident. Despite the years that have passed since the accident, decommissioning remains a concern. Radiation measurement techniques are very important for accelerating the decommissioning and ensuring low radiation exposure to workers. Our gamma-ray imaging system is the detection device for determining the three dimensional radioactive distributions of nuclear fuel debris, measuring high-energy gamma rays (greater than 1 MeV). Silicon semiconductor detectors are among the candidate detectors for radiation measurements in our system because of their radiation-hardness and high counting rate capability. We have been developing a stacked amorphous-silicon (Si)/crystal-Si heterojunction Si strip detector, which has 1-mm-pitch striped electrodes (0.5 mm wide) and 1.2-mm-pitch stacked technology. The detector consists of an Si strip mounted on a thin printed circuit board, front-end readout electronics with a complementary metal oxide semiconductor application specific integrated circuit, and a field programmable gate array. The threshold level of energy deposition of each pulse signal in each channel can be set from the application-specific integrated circuit, and gamma-ray images with energy discrimination can be obtained. The energy threshold level for discrimination of $$^{60}$$Co gamma rays from $$^{137}$$Cs gamma rays was investigated experimentally and by means of simulation, and it was found to be about 500 keV. Therefore, our Si strip detector has the required position sensitivity and energy discrimination ability for identifying high-energy gamma-ray source distributions.

論文

Radiation imaging using a compact Compton camera inside the Fukushima Daiichi Nuclear Power Station building

佐藤 優樹; 谷藤 祐太; 寺阪 祐太; 宇佐美 博士; 冠城 雅晃; 川端 邦明; 宇津木 弥*; 菊地 弘幸*; 高平 史郎*; 鳥居 建男

Journal of Nuclear Science and Technology, 55(9), p.965 - 970, 2018/09

 被引用回数:8 パーセンタイル:11(Nuclear Science & Technology)

The Fukushima Daiichi Nuclear Power Station (FDNPS), operated by Tokyo Electric Power Company Holdings, Inc., went into meltdown after the occurrence of a large tsunami caused by the Great East Japan Earthquake of March 11, 2011. The radiation distribution measurements inside the FDNPS buildings are indispensable to execute decommissioning tasks in the reactor buildings. We conducted the radiation imaging experiment inside the turbine building of Unit 3 of the FDNPS using a compact Compton camera, and succeeded in visualizing the high-dose contamination (up to 3.5 mSv/h). We also drew a three-dimensional radiation distribution map inside the turbine building by integrating the radiation image resulting from the Compton camera into the point cloud data of the experimental environment acquired using the scanning laser range finder. The radiation distribution map shows the position of these contaminations on the real space image of the turbine building. The radiation distribution map helps workers to easily recognize the radioactive contamination and to decrease the radiation exposure; the contamination cannot be observed with the naked eye, naturally.

244 件中 1件目~20件目を表示