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Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
Journal of Nuclear Science and Technology, 59(5), p.656 - 664, 2022/05
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)It is known that internal doses depend on the physical characteristics of an evaluation subject. Internal dose coefficients provided by the International Commission on Radiological Protection (ICRP) are evaluated using the characteristics of the standard Caucasian. It is important to grasp the variations of doses due to the differences in characteristics between Japanese and Caucasian when the dose coefficients of ICRP are applied to Japanese. This study evaluated dose coefficients using specific absorbed fraction (SAF) data based on the average adult Japanese physique which was developed by modification of the existing Japanese SAF data with additional calculations to make the existing data fit to the current dosimetric methodology of ICRP and compared them to those provided by ICRP. As a result, the discrepancies in dose coefficients were smaller than plus or minus 10% in most intake conditions. However, some intake conditions indicated varieties over 40% due to the differences in organ masses, amount of adipose tissues around the thoracic cavity, and so on. This information is useful in application of ICRP's dose coefficients to population of which physical characteristics are different from those of Caucasian. Further, the Japanese SAF data is published as an appendix of this paper.
Yokoyama, Sumi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; Ono, Koji*; et al.
Journal of Radiation Protection and Research, 47(1), p.1 - 7, 2022/03
Background: In Japan, new regulations that revise the dose limit for the lens of the eye (the lens), operational quantities, and measurement positions for the lens dose were enforced in April 2021. Based on the international safety standards, national guidelines, the results of the Radiation Safety Research Promotion Fund of the Nuclear Regulatory Authority, and other studies, the Working Group of Radiation Protection Standardization Committee, the Japan Health Physics Society (JHPS) developed a guideline for radiation dose monitoring for the lens. Materials and Methods: The Working Group of the JHPS discussed the criteria of non-uniform exposure and the management criteria set to not exceed the dose limit for the lens. Results and Discussion: In July 2020, the JHPS guideline was published. The guideline consists of three parts: main text, explanations, and 26 questions. In the questions, the corresponding answers were prepared, and specific examples were provided to enable similar cases to be addressed. Conclusion: With the development of guideline on radiation dose monitoring of the lens, radiation managers and workers will be able to smoothly comply with revised regulations and optimise radiation protection.
Yokoyama, Sumi*; Iwai, Satoshi*; Tsujimura, Norio; Hashimoto, Makoto; Yoshitomi, Hiroshi; Kato, Masahiro*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Sekiguchi, Hiroshi*; Koguchi, Yasuhiro*; et al.
Proceedings of 15th International Congress of the International Radiation Protection Association (IRPA-15) (Internet), 8 Pages, 2022/00
Furuta, Hiroshige*; Sato, Kaoru; Nishide, Akemi*; Kudo, Shinichi*; Saigusa, Shin*
Health Physics, 121(5), p.471 - 483, 2021/11
Times Cited Count:1 Percentile:16.35(Environmental Sciences)Low dose radiation induced "health effects" containing cancer risk for a Japanese radiation worker cohort is epidemiologically evaluated using the personal dose equivalent (Hp(10)). On the other hand, Hp(10) is not recommended for epidemiological evaluation of cancer risks, since the Hp(10) is widely used for radiological protection purposes. In addition, the cancer risk depends on organ doses rather than Hp(10). Thus, we developed a new method for estimating organ doses from Hp(10) of radiation workers. The developed method enables epidemiological analysis against Japanese radiation workers by considering the response characteristics of personal dosimeters, exposure geometry and energy, and body size of radiation workers in Japan. In the future, we will reconstruct organ dose conversion factor and will evaluate the risk of cancer mortality and morbidity using the organ dose in Japan.
Oba, Kyoko
Kogaku Kyoiku, 69(5), p.95 - 98, 2021/09
This paper introduces the recent topics of the Atomic Energy Society of Japan Ethics Committee. In addition, referring to the topics, the abilities and sensibilities that engineers should have in the future will be described.
Uezu, Yasuhiro
Iwaki-Shi, Higashi Nihon Daishinsai Fukko Kiokushu, P. 37, 2021/00
This report describes the response to the Great East Japan Earthquake that occurred on March 11, 2011 from the perspectives of environmental monitoring, internal exposure evaluation, radiation education, and human resource development.
Omori, Yasutaka*; Hosoda, Masahiro*; Takahashi, Fumiaki; Sanada, Tetsuya*; Hirao, Shigekazu*; Ono, Koji*; Furukawa, Masahide*
Journal of Radiological Protection, 40(3), p.R99 - R140, 2020/09
Times Cited Count:22 Percentile:77.11(Environmental Sciences)UNSCEAR and the Nuclear Safety Research Association report the annual effective doses from cosmic rays, terrestrial radiation, inhalation and ingestion from natural sources. In this study, radiation doses from natural radiation sources in Japan were reviewed with the latest knowledge and data. Total annual effective dose from cosmic-ray exposure can be evaluated as 0.29 mSv. The annual effective dose from external exposure to terrestrial radiation for Japanese population can be evaluated as 0.33 mSv using the data of nationwide survey by the National Institute of Radiological Sciences. The Japan Chemical Analysis Center (JCAC) performed the nationwide radon survey using a unified method for radon measurements in indoor, outdoor and workplace. The annual effective dose for radon inhalation was estimated using a current dose conversion factor, and the values were estimated to be 0.50 mSv. The annual effective dose from thoron was reported as 0.09 mSv by UNSCEAR and then the annual effective dose from inhalation can be described as 0.59 mSv. According to the report of large scale survey of foodstuff by JCAC, the effective dose from main radionuclides due to dietary intake can be evaluated to be 0.99 mSv. Finally, Japanese population dose from natural radiation can be assessed as 2.2 mSv which is near to the world average value of 2.4 mSv.
Nakamura, Hideo
Nihon Genshiryoku Gakkai-Shi ATOMO, 61(4), p.270 - 272, 2019/04
no abstracts in English
Oba, Kyoko
Nihon Genshiryoku Gakkai-Shi ATOMO, 61(4), p.347 - 348, 2019/04
This article is published in a special feature in commemoration of the 60th anniversary of the Atomic Energy Society of Japan. The article is the contents that "I look back on this, and surveys the future", by chairwoman of Ethics Committee.
Naraha Center for Remote Control Technology Development, Fukushima Research Insitute
JAEA-Review 2018-014, 52 Pages, 2018/12
The Naraha Remote Technology Development Center (Naraha Center) consists of a mock-up test building and a research management building, and various test facilities necessary for the decommissioning work after the accident of TEPCO Fukushima Daiichi Nuclear Power Station are installed. Using these test facilities, a wide range of users, such as companies engaged in decommissioning work, research and development institutions, educational institutions, etc., can efficiently develop robots through characterization and performance evaluation of remote-controlled robots. Furthermore, it is possible to make various uses such as exhibitions that many companies have met together, experts' meetings on decommissioning. This report summarizes the activities of the Naraha Center such as development of remote control technologies, maintenance and training of remote control equipment for emergency response, use of component test areas, and so on in FY2016.
Khim, B.-K.*; Otosaka, Shigeyoshi; Park, K.-A.*; Noriki, Shinichiro*
Ocean Science Journal, 53(1), p.17 - 29, 2018/03
Times Cited Count:5 Percentile:27.02(Marine & Freshwater Biology)Distribution of carbon and nitrogen stable isotope ratios (C, N) in sinking particles collected in four stations in the Japan Sea was summarized. The C and N values in the sinking particles showed a clear seasonal variation, which agreed well with the variation in the chlorophyll a concentration in the surface seawater and in the sinking flux of biogenic particles. In particular, during the highly productive season of phytoplankton, a remarkable isotopic fractionation of N was found in the sinking particles, and it was inferred that the fractionation indicates the degree of nitrogen uptake by diatoms in the surface layer. These results are helpful information for linking the phenomenon in the ocean surface and the isotopic information recorded in the seafloor.
Sato, Kaoru; Takahashi, Fumiaki
Hoken Butsuri, 52(4), p.247 - 258, 2017/12
Organ doses for dose assessment in radiation protection are derived from ICRP reference phantoms (Male:RCP-AM, Female:RCP-AF) with standard Caucasian physiques. In adult, Japanese are smaller than Caucasian. To study impact of differences in physiques between Caucasian and Japanese on organ doses, we previously constructed Japanese phantoms (Male:JM-103, Female:JF-103) with average adult Japanese physiques. In addition, adult Japanese physiques have also wide distribution. Thus, we newly modeled DJM (Male) and DJF (Female) with 8 physiques by changing the perimeters of JM-103 and JF-103. Organ doses due to external photon irradiation of DJM and DJF were calculated, and were compared with those of RCP-AM and RCP-AF. In ISO geometry at 0.3 MeV, it was found that doses of breast, colon, lung, stomach, gonad, urinary bladder, esophagus, liver and thyroid in DJM and DJF with physiques, which are applicable to most adult Japanese, agreed with those of RCP-AM and RCP-AF within 10%.
Yoshinaka, Kazuyuki
Gijutsushi, 29(11), p.12 - 15, 2017/11
We visited Onagawa NPP and discussed with the workers, for study of good practices at this plant, avoided severe accident, when the 3.11 earthquakes and tsunami disaster occurred. It was learned a part of background of the good practices, by discussion about organizational culture included in attitude for safety, philosophy of management, inheritance technology, and so on. It is important that we inform the knowledge leading safety culture analyzed from their experience to public, as professional engineer.
Sasaki, Satoru
Nihon Genshiryoku Gakkai-Shi ATOMO, 59(4), p.192 - 193, 2017/04
The institution of Professional Engineers, Japan (lPEJ), and the activity of contribution to society of IPEJ after the Fukushima-Daiichi Nuclear Power Plant accident were described.
Ishihara, Keisuke; Kanazawa, Shingo; Kozawa, Masachiyo; Mori, Masakazu; Kawahara, Takahiro
JAEA-Technology 2017-002, 27 Pages, 2017/03
At radioactive waste management facilities in the Nuclear Science Research Institute, solid radioactive wastes are stored by using containers such as 200L drums and pallets to tier containers in 2 to 4 stacks in the height direction in waste storage facilities (Waste Storage Facility No.1, Waste Storage Facility No.2 and Waste Size Reduction and Storage Facility). On March 11, 2011, the Great East Japan Earthquake was happened, and some waste packages dropped from their pallets and large number of waste packages moved from their original position and inclined due to the influence of the earthquake in the waste storage facilities. There was no experience of rearrangement works to set those dropped and unbalanced waste packages in their original position and it was necessary to prepare detailed work procedures and progress for this task to prevent the occurrence of industrial accidents. Therefore, we prepared detailed work manual and repeatedly carried out mock-up test. And then, we started rearrangement work from April 2011 after confirmation of workers skill and adequacy of the work manual. Finally, all rearrangement works for stored waste packages took about four and half years and were completed in September 2015 without any accident and shutdown of storage function. This report summarizes the countermeasures to reduce exposure doses of workers and to prevent the occurrence of industrial accidents during the rearrangement works.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
JAEA-Data/Code 2016-013, 48 Pages, 2016/12
In the 2007 Recommendations of the International Commission on Radiological Protection (ICRP), an effective dose is defined as a sum of equivalent doses which are calculated by using male and female reference phantoms based on Caucasian physiological data and averaged over the sexes by tissue weighting factors. Specific absorbed fractions (SAFs), which are essential for internal dosimetry, depend on the body weight and organ masses of phantoms. Then, the dose coefficients, which are committed effective doses per unit intake of radionuclides, developed by ICRP on the basis of the 2007 Recommendations reflect the physical characteristics of Caucasians and are averaged over the sexes. Meanwhile, the physiques of adult Japanese are generally smaller than those of adult Caucasians, and organ masses are also different from each other. Knowledge of the influence of race differences on dose coefficients is important to apply the sex averaged dose coefficients of ICRP to the Japanese system of radiation protection. In this study, SAFs for 25 kinds of mono-energetic electrons and photons ranging from 10 keV to 10 MeV were calculated about the combinations of 67 source regions and 42 target organs using the average adult Japanese female phantom, JF-103, incorporated with a general purpose radiation transport code, MCNPX 2.6.0. The data of this report and the previously published data of JM-103 are applicable to evaluate sex-specific and sex-averaged dose coefficients reflecting the physical characteristics of the average adult Japanese for intakes of all radionuclides not to emit other than photons and electrons.
Sasaki, Satoru
Hoshasen, 41(2), p.89 - 92, 2016/03
Professional Engineer is the national qualification stipulated by the Professional Engineer Act. A Professional Engineer in this Act means a person who conducts business on matters of planning, research, design, analysis, testing, evaluation or guidance thereof, which requires application of extensive scientific and technical expertise, and has three obligation and two responsibility related to engineer ethic. A technical discipline for nuclear and radiation technology in 2004, was established for the purpose of upgrading the skills of engineers in nuclear technology fields, utilizing their ability in nuclear safety regulation fields, and further strengthening safety management system in each entity. The activity of the nuclear and radiation professional engineers for the past 10 years was evaluated. For the next ten years, awareness of the role of the professional engineer to talk with general public is needed, and it is important to continue professional development.
Yamasoto, Kotaro
Gijutsushi, 27(11), p.8 - 11, 2015/11
Various analysis reports focused on Fukushima Daiichi Nuclear Power Plant disaster have been published from government, national diet, private group and Tokyo electric power company. Japan Health Physics Society (JHPS) analyzed these reports on perspective of radiation protection, and has reported towards the national and international society as "second-order recommendation report". What are radiation protection issues that have been found from these analysis reports? What is the direction of the goal of radiation protection system at the time of nuclear accident? From the results of these analyzes, many challenges have been found in current nuclear disaster prevention system.
Takahara, Shogo; Iijima, Masashi; Shimada, Kazumasa
Hoken Butsuri, 50(3), p.172 - 181, 2015/09
Takahashi, Fumiaki; Sato, Kaoru; Endo, Akira; Ono, Koji*; Ban, Nobuhiko*; Hasegawa, Takayuki*; Katsunuma, Yasushi*; Yoshitake, Takayasu*; Kai, Michiaki*
Health Physics, 109(2), p.104 - 112, 2015/08
Times Cited Count:8 Percentile:56.13(Environmental Sciences)A dosimetry system, named WAZA-ARI, is developed to assess accurately radiation doses to persons from Computed Tomography (CT) examination patients in Japan. Organ doses were prepared to application to dose calculations in WAZA-ARI by numerical analyses using average adult Japanese human models with the Particle and Heavy Ion Transport code System (PHITS). Experimental studies clarified the radiation configuration on the table for some multi-detector row CT (MDCT) devices. Then, a source model in PHITS could specifically take into account for emissions of X-ray in each MDCT device based on the experiment results. Numerical analyses with PHITS revealed a concordance of organ doses with human body size. The organ doses by the JM phantoms were compared with data obtained using previously developed systems. In addition, the dose calculation in WAZA-ARI were verified with previously reported results by realistic NUBAS phantoms and radiation dose measurement using a physical Japanese model. The results implied that analyses using the Japanese phantoms and PHITS including source models can appropriately give organ dose data with consideration of the MDCT device and physiques of typical Japanese adults.