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Akiyama, Yoichi; Shibanuma, So; Yanagisawa, Kenichi*; Yamada, Taichi; Suzuki, Kenta; Yoshida, Moeka; Ono, Takahiro; Kawabata, Kuniaki; Watanabe, Kaho; Morimoto, Kyoichi; et al.
JAEA-Review 2023-015, 60 Pages, 2023/09
JAEA-Review-2023-015.pdf:4.78MB
Naraha Center for Remote Control Technology Development (NARREC) was established in Japan Atomic Energy Agency to promote a decommissioning work of Fukushima Daiichi Nuclear Power Station (Fukushima Daiichi NPS). NARREC consists of a Full-scale Mock-up Test Building and Research Management Building. Various test facilities are installed in these buildings for the decommissioning work of Fukushima Daiichi NPS. These test facilities are intended to be used for various users, such as companies engaged in the decommissioning work, research and development institutions, educational institutions and so on. The number of NARREC facility uses was 84 in FY2021. We participated booth exhibitions and presentations on the decommissioning related events. Moreover, we also contributed to the development of human resources by supporting the 6th Creative Robot Contest for Decommissioning. As a new project, "Narahakko Children's Classroom" was implemented for elementary school students in Naraha Town. This report summarizes the activities of NARREC in FY2021, such as the utilization of facilities and equipment of NARREC, the development of remote-control technologies for supporting the decommissioning work, arrangement of the remote-control machines for emergency response, and training for operators by using the machines.
Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*
Journal of Radiological Protection, 42(4), p.041503_1 - 041503_12, 2022/12
Times Cited Count：1 Percentile：31.61(Environmental Sciences)Sheltering is one of the countermeasures against radiation exposure during nuclear accidents. The effectiveness of sheltering for inhalation exposure is often expressed by the reduction factor, which is defined as the ratio of the indoor to the outdoor cumulative radioactivity concentrations or doses. The indoor concentration is mainly controlled by the air exchange rate, penetration factor, and indoor deposition rate. Meanwhile, the air exchange rate depends on surrounding environmental conditions: the wind speed, leakage area normalized by the floor area of the house, and gross building coverage ratio. In this study, the ranges of the uncertainty of the reduction factors for particles and I
were investigated under various environmental conditions, and sensitivity analyses were conducted to understand the parameter with the most influence on the uncertainty of the reduction factor. From the results of the uncertainty analyses, the calculated reduction factor was highly variable depending on the environmental condition and the airtightness of the houses. The uncertainty ranges of the reduction factor for particles and I were up to 0.9 and 0.3, respectively, and were smaller for newer houses. From the results of the sensitivity analyses, the wind speed was the most influential parameter on the reduction factor. Additionally, the wind speed was less influential for the reduction factor in newer houses.
Hiraoka, Hirokazu; Komatsuzaki, Joji*; Hanaka, Norihiko*; Okamoto, Akiko; Saito, Yoshihiko*; Munakata, Masahiro; Togawa, Orihiko
JAEA-Technology 2022-003, 70 Pages, 2022/07
JAEA-Technology-2022-003.pdf:2.53MB
In contamination inspections for public in nuclear emergency, it is assumed that a large number of motor vehicles and evacuees will be inspected. At present, first measurement points of vehicles are tires and around a wiper, and they are basically inspected by persons using portable radiation surface contamination meters such as GM survey meters. However, in order to efficiently inspect contamination of vehicles, utilization of portable radiation portal monitors is being considered for the inspection. In this study, examination of performance of the portal monitor was conducted in order to obtain basic data. In this examinations, sealed radiation sources, 
Ba, were substituted for the contamination of Operational Intervention Level 4 (OIL4), the evaluation criteria to conduct simple decontamination in the contamination inspection. The radiation source was attached practically to a tire and around the wipers of a vehicle, and the counting rate of 
-rays from the radiation sources was measured using the portal monitor. Three examinations were conducted: static examination with a vehicle stationary, moving examination to mock the actual inspection, and high back ground examination to investigate performance of the equipment in high back ground environment. The vehicle mainly used in the experiments was a sedan, which is generally used as standard vehicles. And, a van whose front body is like that of a bus was used at this experiment. In addition, the "Gamma Pole" manufactured by the Chiyoda Technol Corporation was used as the portal monitor. As the result, it was estimated that the case of contamination equivalent to 40,000 cpm, the default value of the OIL4, deposited on the tread on a vehicle tire, when the vehicle passes through the portal monitor at 10 km/h or less, the contamination would be detected with a probability of 99% or more. Similarly, when the contamination deposited on around the wipers and the vehicle speed is 5 km/h or less,
Yamada, Taichi; Kawabata, Kuniaki; Abe, Hiroyuki*
JAEA-Technology 2021-033, 18 Pages, 2022/03
JAEA-Technology-2021-033.pdf:1.58MB
This report describes the test procedures for evaluating performances involved in robot arm maneuvering of remotely operated robot utilized for nuclear emergency responses and decommissioning. After the accident at Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company Holdings Inc. (FDNPS) occurred, remotely operated robots have been deployed and utilized in the response tasks. Such post-accident work experience and lessons learned are very valuable for developing the robots in the future. Therefore, we were motivated to develop the test methods for performance evaluation of the robot by referring with such experiences and lessons. In the response and the decommissioning tasks, robots with a robot arm were deployed for door opening, removal objects, decontamination and cleanup and so on. Some of these tasks were conducted in an environment with obstacles by robot arms maneuvering. This report describes test procedures for quantitatively evaluating the performances which are for maneuvering involving in robot arm to approach target objects in an environment with obstacles. A typical course layout and the demonstration of test are also illustrated for the references.
Kawabata, Kuniaki; Yamada, Taichi; Abe, Hiroyuki*
JAEA-Technology 2021-021, 30 Pages, 2021/11
JAEA-Technology-2021-021.pdf:2.55MB
This report describes the test procedures for performance evaluation of remotely operated robot utilized for nuclear emergency responses and decommissioning that provide to compare among the robot's performances quantitatively and relatively. After the accident at Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company Holdings Inc. (FDNPS) occurred, remotely operated robots have been deployed and utilized in the response tasks. Such post-accident work experiences and lessons learned are very valuable for developing the robots in the future. Therefore, we were motivated to develop the test methods for performance evaluation of the robot by referring with such experiences and lessons. In recent decommissioning tasks, reconnaissance on the distribution and status of nuclear fuel debris inside the Primary Containment Vessel (PCV) have been carried out. The insertion and deployment of robots into PCV were carried out through a penetration pipe with small diameter to prevent the scattering of radioactive materials. According to the authors' survey on such works have carried out in Units 1 and 2 of FDNPS, in order to carry out the reconnaissance work by the robot deployed into the PCV, it was clarified that the robots are required to run freely on the floor located below the exit of the penetration pipe and run freely on the inclined surface located below the exit of the pipe. This document describes two test procedures for performance evaluation of the robot connected with the cable such as running on the floor after being deployed through a penetration pipe and running on the inclined surface after being deployed through a penetration pipe. Typical course layout and the demonstration of test running are also illustrated for the references.
Shimada, Kazumasa; Takahara, Shogo
JAEA-Review 2021-013, 142 Pages, 2021/09
JAEA-Review-2021-013.pdf:4.74MB
In this report, the authors reviewed the published reports of Evacuation Time Estimation (ETE) conducted in Japan and United States and examined the issues of ETE in Japan. The authors obtained public ETE reports in Japan from 16 prefectures up to February 2020. In addition, the authors obtained 58 ETE reports in United States from 2011 to 2018. Next, the overview of ETE for the Emergency Planning Zone (EPZ) around the nuclear power plant in United States was described based on the NUREG/CR-7002 of the U.S Nuclear Regulatory Commission (NRC). Then, based on the guidance of the ETE of the Cabinet Office of Japan, the overview of ETE in Japan for the Precautionary Action Zone (PAZ) and the Urgent Protective Action Planning Zone (UPZ) was described and compared with the ETE in United States. It was found that ETE in Japan often outputs only the time of 90% or 100% that population complete evacuation. Therefore, in order to use ETE in Japan for emergency decision-making, it is necessary to unify the inputs and outputs of ETE as in the United States' ETE reports.
Kawabata, Kuniaki; Yamada, Taichi; Abe, Hiroyuki*
JAEA-Technology 2020-015, 37 Pages, 2020/11
JAEA-Technology-2020-015.pdf:3.81MB
This report describes the test procedures for evaluating running performances of remotely operated robot utilized for nuclear emergency responses and decommissioning. After the accident at Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company Holdings Inc. (FDNPS) occurred, remotely operated robots have been deployed and utilized in the response tasks. Such post-accident work experience and lessons learned are very valuable for developing the robots in the future. Therefore, we were motivated to develop the test methods for performance evaluation of the robot by referring with such experiences and lessons. Based on our examinations, in order to execute the response and decommissioning tasks, the robots are required to run through the space without enough margin and avoiding collisions, to move on stairs while avoiding tumbling or falling down and to drag a cable while avoiding problems caused by the cable entwining around objects. This report describes three test procedures for quantitatively evaluating the performances which are for running narrow passage, climbing up/down on the stairs and running with dragging the cable. Typical course layout and the demonstration of test running are also illustrated for the references.
Kawabata, Kuniaki
Japanese Journal of Applied Physics, 59(5), p.050501_1 - 050501_9, 2020/05
Times Cited Count：11 Percentile：18.54(Physics, Applied)This paper describes the decommissioning work being undertaken at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company Holdings Inc.'s (FDNPS) using remote controlled robotic systems, as well as lessons learned from past remote task executions. We also summarize the issues to be considered in promoting safe, steady, and efficient decommissioning based on past experiences. In response to these issues, we are developing test methods for performance evaluation of the robots for nuclear decommissioning, robot simulator for operator proficiency training, and information generation methods to improve the operator's status awareness. The current status of technological development is also described.
Hiraoka, Hirokazu; Hokama, Tomonori; Munakata, Masahiro
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 5 Pages, 2019/05
Neighboring inhabitants of nuclear facilities must evacuate according to an ambient dose rate at a nuclear accident. The evacuation is judged by the measured value by monitoring posts (MPs). However, if the measured value increase by artificial radionuclide deposited to MP, it is considered that the dose rate of the surrounding environment is overestimated. The purpose of this research is to evaluate exactly the dose rate even if the radionuclide deposit to the MP, in order to adequately evacuate inhabitants. Just a MP and horizontal ground was simulated. To calculate ambient dose rates from the roof surface of MP and ground surface, Monte Carlo calculation was done. And, it was obtained that the ratio which the dose rate from the roof account for sum of two these dose rates. According to the result, the ratio was 42%. It suggested that the radionuclide could increase the measured value. However, because simulated system was simple, it is considered that the ratio was overestimated.
Chiba, Yusuke; Nishiyama, Yutaka; Tsubaki, Hirohiko; Iwai, Masaki
JAEA-Technology 2019-002, 29 Pages, 2019/03
JAEA-Technology-2019-002.pdf:2.43MB
Act on Special Measures Concerning Nuclear Emergency Preparedness was amended on the 30th of October in 2017. As the JAEA Emergency Assistance Organization, Maintenance and Operation Section for Remote Control Equipment in Naraha Center for Remote Control Technology Development started training for emergency response robots operation for operators in each site of JAEA in response to the new amendment. The training consists of three operations: small crawler-type mobile scouting robots, big crawler-type mobile robots with a manipulator or a long tong and small radio-controlled helicopters. The training has three classes (beginner, intermediate and advanced classes) depending on skills and experiences. This paper reports the training programs of emergency response robots operation of the beginner and intermediate classes which were used in the first half of fiscal 2018.
Kawabata, Kuniaki
Nihon Robotto Gakkai-Shi, 36(7), p.460 - 463, 2018/09
no abstracts in English
Nozawa, Masao*; Watanabe, Norio
Proceedings of US-Japan Workshop on the Role of Nuclear Energy in a New Environment of Deregulation and Climate Change, 14 Pages, 2000/10
no abstracts in English
Han, C. Y.*; Ebata, Shuichiro*; Sagara, Hiroshi*; Takeshita, Kenji*; Matsumoto, Yoshihisa*; Chiba, Satoshi*; Furuno, Akiko; Nagai, Haruyasu
no journal, ,
In Tokyo Institute of Technology, the nuclear human resource development program, "the Advanced Nuclear 3S Education and Training (ANSET)", was established in 2017, supported by Nuclear Regulatory Authority. This paper introduces the exercise on "Environmental Dynamics of Radioactive Material" of this program.
Kawabata, Kuniaki; Yamada, Taichi; Shirasaki, Norihito; Ishiyama, Hiroki
no journal, ,
Kawabata, Kuniaki; Yamada, Taichi; Abe, Hiroyuki*
no journal, ,
In this paper, we describe the efforts of Japan Atomic Energy Agency to develop performance test methods for nuclear disaster response robots. We have referred to the experiences in the tasks performed by using remotely operated robots and the characteristics of working space in the accident response and decommissioning work of the Fukushima Daiichi Nuclear Power Station and extract the performance that the nuclear disaster response robot should have. We are currently developing performance test methods for quantitative evaluation on them. We introduce the performance test methods that have been developed and also the tests that are currently under development.
Hiraoka, Hirokazu; Hokama, Tomonori; Munakata, Masahiro
no journal, ,
Neighboring inhabitants of nuclear facilities must evacuate according to an ambient dose rate at a nuclear accident. The evacuation is judged by the measured value by monitoring posts (MPs). However, if the measured value increase by artificial radionuclide deposited to MP, it is considered that the dose rate of the surrounding environment is overestimated. The purpose of this research is to evaluate exactly the dose rate even if the radionuclide deposit to the MP, in order to adequately evacuate inhabitants. Just a MP and horizontal ground was simulated. To calculate ambient dose rates from the roof surface of MP and ground surface, Monte Carlo calculation was done. And, it was obtained that the ratio which the dose rate from the roof account for sum of two these dose rates. According to the result, the ratio was 44%. It suggested that the radionuclide could increase the measured value. However, because simulated system was simple, it is considered that the ratio was overestimated.
Iguchi, Shintaro; Horiguchi, Hironori; Araki, Masaaki
no journal, ,
The intervention level on the practical use by which the principle measurement which are the spatial radiation dose rate and the density of the radioactive materials in the environment sample, etc. as the standard by which implementation of protective measure is judged is expressed in the possible price (OIL) is established by the atomic disaster countermeasures guideline an atomic regulatory committee set. The dose evaluation when changing the fuel damaged percentage conservatively about over the design basic accident of JRR-3 and the reactor core way way blockade accident, was put into effect and OIL1 and OIL2 were compared with the implementation standard of the protective measure by this publication. Just after flow pass of a fuel element was blocked up, radioactive materials are damaged, and are released from fuel to a cooling system, and an evaluation phenomenon and a done reactor core way way blockade accident are the accident released from exhaust equipment for emergency use to ambient surroundings via a shift to a nuclear reactor pool and a building. It didn't operate with the case when exhaust equipment for emergency use normally operated by evaluation, and the occasion which did the ground release was assumed. The dose rate by the nuclide released in the atmosphere from a nuclear reactor building and the dose rate by the nuclide floating in the nuclear reactor building were estimated about dose evaluation. The evaluation point was made a distance 329m spot from JRR-3 to the atomic scientific research place site boundary. It was confirmed that there are also no dose rates beyond the initialization value of OIL1 in the result and just after accident. It was confirmed that the dose rate falls and falls below the initialization value of OIL2 after 6 time course rapidly after an accident.
Hiraoka, Hirokazu; Kawasaki, Kohei*; Kimura, Masanori; Togawa, Orihiko; Saito, Shota; Ezaki, Iwao*
no journal, ,
When the nuclear emergency occurs, inhabitants take the contamination inspection to evacuate. A large number of vehicle will come to the inspection area and make there congested. To do the quick inspection, simultaneous measurement of tires and wipers using the portable radiation portal monitors for vehicles is a key point. Consequently, we attempted the count rates obtained from tires and wipers are discriminated. First, the vehicle was driven at 5 km/h and the -ray counts rate was measured by the monitor. Ba sources were attached around the tire or on the wiper and measurements were taken 30 times each. Next, discrimination conditions based on a linear function were applied to the normalized count rates, with the maximum count rate of the measured values (Net value) set to 1.0, to evaluate the discrimination accuracy between the tire and the wiper. The evaluation results showed that the pattern with the source attached around the tire correctly discriminated 29 out of 30 times, while the pattern with the source attached on the wiper correctly discriminated 20 out of 30 times. It was found that in order to improve the accuracy of discrimination, the measurement method must be improved so that there is a large difference between measured values of the tire and the wiper.
Tagawa, Akihiro
no journal, ,
The presentation will cover risk communication that has been conducted since immediately after the earthquake and the lessons learned.
Kawasaki, Kohei*; Hiraoka, Hirokazu; Ezaki, Iwao*; Kimura, Masanori; Togawa, Orihiko; Saito, Shota
no journal, ,
Vehicles carrying evacuees during a nuclear emergency are subject to contamination inspections, and the operation of screening by measuring tires and wiper are required. The introduction of portable radiation portal monitors for vehicles is expected to be quick tire inspections, however, it is difficult to inspect the tire and the wiper at the same time, so further speeding up the inspection process is an issue. In this study, we attempted to discriminate each type of contamination by using a different the new set up of detectors for the purpose of simultaneous inspection of tires and wiper. We will report the usefulness of the new set up and the results of simulation calculations of detector response under realistic contamination assumptions.
