Trends in radiation standard; Current status of secondary standards at JAEA

Tanimura, Yoshihiko; Yoshitomi, Hiroshi

Nihon Genshiryoku Gakkai-Shi ATOMO, 66(1), p.42 - 45, 2024/01

https://doi.org/10.3327/jaesjb.66.1_42

no abstracts in English

Arrangements for telephone consultation on radiation health effects in a nuclear emergency in Japan; Lessons learned from the nuclear accident in Fukushima, Japan, 2011

Okuno, Hiroshi; Kawakami, Takeshi; Watanabe, Fumitaka; Horikoshi, Hidehiko*

Journal of Disaster Research, 18(8), p.911 - 917, 2023/12

https://doi.org/10.20965/jdr.2023.p0911

In response to residents' concerns about the radiation health effects following the nuclear accidents at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company in March 2011, the Japan Atomic Energy Agency (JAEA) established a telephone consultation system. Eight toll-free telephone lines were prepared, and employees with knowledge of radiation health effects were assigned for consultation. Approximately 35,000 consultations were conducted from March 17, 2011, to September 18, 2012. The results of the text mining analysis revealed that the greatest source of anxiety was the impact on children's health from radiation. The JAEA's system for telephone consultation was improved following this telephone consultation experience. The description of telephone hotlines in the International Atomic Energy Agency (IAEA) guide, GSG-14, was discussed for further improvements of the JAEA's telephone consultation system.

Current location of fuel debris chemistry

Sato, Nobuaki*; Kirishima, Akira*; Sasaki, Takayuki*; Takano, Masahide; Kumagai, Yuta; Sato, Soichi; Tanaka, Kosuke

Current Location of Fuel Debris Chemistry, 178 Pages, 2023/11

Considerable efforts have been devoted to the decommissioning of the TEPCO's Fukushima Daiichi Nuclear Power Station (1F) and now the retrieval of fuel debris is being proceeded on a trial basis. It can be said that the succession of science and technology related to debris, that is, human resource development, is important and indispensable. For that reason, we thought that a specific textbook on decommissioning is necessary. Regarding the 1F fuel debris, we still do not know enough, and it would be difficult to describe the details. However, 12 years have passed since the accident, and we have come to understand the situation of 1F to a certain extent. At this stage, it is essential for future development to organize the current situation by combining examples of past severe accidents. Therefore, we presented in this book the current state of fuel debris chemistry research from the perspectives of solid chemistry, solution chemistry, analytical chemistry, radiochemistry, and radiation chemistry.

First-principles simulation of an ejected electron produced by monochromatic deposition energy to water at the femtosecond order

Kai, Takeshi; Toigawa, Tomohiro; Matsuya, Yusuke; Hirata, Yuho; Tezuka, Tomoya*; Tsuchida, Hidetsugu*; Yokoya, Akinari*

RSC Advances (Internet), 13(46), p.32371 - 32380, 2023/11

https://doi.org/10.1039/D3RA05075K

Although scientific knowledge of photolysis and radiolysis of water is widely used in the life sciences and other fields, the formation mechanism of the spatial distribution of hydrated electrons (spur) resulting from energy deposition to water is still not well understood. The chemical reaction times of hydrated electrons, OH radicals, and HO in the spur strongly depend on the spur radius. In our previous study, we elucidated the mechanism at a specific given energy (12.4 eV) by first-principles calculations. In the present study, we performed first-principles calculations of the spur radius at the deposition energies of 11-19 eV. The calculated spur radius is 3-10 nm, which is consistent with the experimental prediction (~4 nm) for the energy range of 8-12.4 eV, and the spur radius gradually increases with increasing energy. The spur radius is a new scientific knowledge and is expected to be widely used for estimating radiation DNA damage.

Citizen science observation of a gamma-ray glow associated with the initiation of a lightning flash

Tsurumi, Miwa*; Enoto, Teruaki*; Ikkatai, Yuko*; Wu, T.*; Wang, D.*; Shinoda, Taro*; Nakazawa, Kazuhiro*; Tsuji, Naoki*; Diniz, G.*; Kataoka, Jun*; et al.

Geophysical Research Letters, 50(13), p.e2023GL103612_1 - e2023GL103612_9, 2023/07

https://doi.org/10.1029/2023GL103612

Compton camera measurements of radiation distribution images at Hamadori, Fukushima Prefecture

Kawahara, Rika*; Ochi, Kotaro; Yamaguchi, Katsuhiko*; Torii, Tatsuo*

Hoshasen (Internet), 48(2), p.43 - 48, 2023/04

The accident at the Fukushima Daiichi NPP resulted in a large amount of radioactive material being dispersed into the surrounding environment. It is important to understand the radiation distribution in the area, which is still located in the difficult-to-return zone. In this study, a Compton camera and an optical camera were combined to produce a three-dimensional distribution map of source locations and their intensities. Two locations in the difficult-to-return zone (Okuma town) were surveyed: a park parking lot and the area around a private house. The distribution of air dose rates was determined by measurements with a survey meter with a wand-type GPS (Gamma Plotter H manufactured by Nippon Radiation Engineering Co. Measurements were taken with a Compton camera (H420, H3D, USA) at several different positions and angles towards the hotspots. The software (Application Programming Interface Example) allowed real-time confirmation of the radiation incident information (incident time, energy, x, y, z) obtained by the Compton camera. By photographing hotspots in high-dose areas from different positions and angles, the location of the radiation sources and their spatial extent could be confirmed.

Establishment of JIS testing laboratory for radiation monitoring instruments

Yoshitomi, Hiroshi

Isotope News, (786), p.26 - 29, 2023/04

no abstracts in English

Fact-finding survey on the competencies and literacy of radiological technologists regarding radiation disasters

Arai, Tomohiro*; Murata, Sho*; Watanabe, Yuichi*; Ishihara, Toshihiro*; Fukamizu, Yoshiya*; Takeda, Satoshi*; Ebata, Kiyokadzu*; Watanabe, Yuki; Takashima, Yoshio*; Kaneko, Junichi*

Journal of X-Ray Science and Technology, 31(2), p.237 - 245, 2023/03

https://doi.org/10.3233/XST-221341

Radiological technologists have received specialized education about radiation and serve as risk communicators who aim to lessen patients' anxiety about radiation exposure, in addition to performing radiological examinations in routine clinical practice. Also, Radiological technologists across Japan were dispatched to the affected area to conduct an essential procedure-screening the belongings and body surfaces of evacuees for contamination at the nuclear disaster at the Fukushima Daiichi Nuclear Power Plant operated by Tokyo Electric Power Company in March 2011. In this study, we conducted a fact-finding survey on knowledge and awareness of radiation disasters among radiological technologists at National Hospital Organization facilities in Japan to reveal their literacy and competencies regarding radiation disasters. Also, we compared the knowledge and awareness of radiation disasters among Japanese radiological technologists between nuclear power station areas and non-nuclear power station areas and discuss ideal human resource development for radiological technologists to be ready to serve during a radiation disaster.

Photon dose rate distribution inside and outside a brachytherapy room

Sabri, A. H. A.*; Tajudin, S. M.*; Aziz, M. Z. A.*; Furuta, Takuya

Radiological Physics and Technology, 16(1), p.109 - 117, 2023/03

https://doi.org/10.1007/s12194-023-00703-8

The spatial distributions of photon dose rates in a brachytherapy room with an Iridium-192 were simulated by using the particle and heavy ion transport code system (PHITS). A geometry of the brachytherapy room with concrete walls and a sliding lead door was reproduced by tracing the existing room in Advanced Medical and Dental Institute at the Universiti Sains Malaysia in Penang. The simulation results were confirmed by comparing to the measured results using a thermoluminescent dosimeter. The simulation study suggested that an additional layer of 3-mm thick lead at the side wall of the entrance will efficiently reduce the dose outside the entrance due to the photons leaked from the edge of the entrance. Simulation with replacing the source with Cobalt-60 was also conducted and revealed the dose level outside the room was too high compared to regulatory value in the current room configuration.

Annual report of Nuclear Emergency Assistance and Training Center (April 1, 2021 - March 31, 2022)

Nuclear Emergency Assistance and Training Center

JAEA-Review 2022-044, 58 Pages, 2022/12

JAEA-Review-2022-044.pdf:3.83MB

The Japan Atomic Energy Agency (JAEA) is one of the designated public corporations, which is the agency dealing with emergency situations in cooperation with the Japanese and local governments under the Disaster Countermeasures Basic Act and under the Armed Attack Situation Response Law. JAEA has, therefore, responsibilities of providing technical assistances to the Japanese and local governments in case of nuclear or radiological emergencies based on these acts. To fulfill the assistances, the JAEA has prepared the Nuclear Emergency Support Measures Regulation, Disaster Prevention Work Plan and Civil Protection Work Plan. The Nuclear Emergency Assistance and Training Center (NEAT) is the main center of the technical assistance in case of emergency, and dispatches experts of JAEA, supplies equipment and materials and gives technical advice and information, to the Japanese and local governments for emergency based on the regulation and plans. In normal time, the NEAT provides the technical assistances such as the exercises and training courses concerning the nuclear preparedness and response to the JAEA experts and to emergency responders including the Japanese and local government officers. This report introduces the results of activities in Japanese fiscal year 2021, conducted by the NEAT.