39 0 0 0 OA 東海再処理施設と環境中のヨウ素-129
- 著者
- 中野 政尚
- 出版者
- 一般社団法人日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.56, no.1, pp.17-25, 2021-03-31 (Released:2021-05-26)
- 参考文献数
- 33
- 被引用文献数
- 1
The Tokai Reprocessing Plant is the first reprocessing plant in Japan which started hot test in 1977, and had reprocessed 1,140 tons of spent nuclear fuel by May 2007. The gaseous and liquid radioactive wastes have been discharged to the environment. Since iodine-129 (129I) is one of the most important nuclides for the long-term environmental impact assessment. Therefore, 129I in the exhaust and effluent has been controlled, and precise analysis methods of 129I in the environmental samples have been developed, and the concentrations of 129I in the various environmental samples have been investigated. This report presents an overview of these activities. Not limited to 129I on the reprocessing facilities, it is essential for nuclear operators to reduce the amount released to the environment in the spirit of ALARA, and to continuously develop the further upgrading environmental monitoring methods and evaluation methods in order to foster a sense of safety and security among residents living in the vicinity of the facilities.
10 0 0 0 OA 金属配管廃材で検知された自然起源の放射性堆積物に関する放射線防護学的な論点と課題
- 著者
- 小池 弘美 甲斐 倫明 飯本 武志
- 出版者
- 一般社団法人日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.57, no.3, pp.140-145, 2022-12-29 (Released:2023-02-09)
- 参考文献数
- 16
Relatively high levels of radioactivity were detected from the handball goal post that had been placed in the schoolyard of an elementary school in Nobeoka City, Miyazaki Prefecture, since around 1997. In November 2021, the goal post was to be removed, and it was transferred to a scrapping company through a waste disposer commissioned by Nobeoka City. Radiation monitoring at the time of transport detected the surface dose rates of 20–30 μSv/h at maximum from the pipe scale of the goal post. The goal post was found to have been apparently handmade by reusing scrap metal pipes. The components and radioactivity adhering to the interior of the pipe are measured and analyzed. Mineralogical analysis shows that the naturally occurring radioactive materials (NORM) contained mainly gypsum, gorgeyite, and baryte. The total radioactivity was evaluated to be 54.5 MBq to be equivalent to 226Ra by a preliminary estimation. The specific activity of the collected sample was 0.6 MBq/kg in the same nuclide. This case may be one of the typical examples of NORM in Japan, and four points in terms of radiation protection are discussed, clarification of the scientific and technical mechanisms of NORM generation, formulation of systematic and specific guidelines on the estimation of NORM according to the purpose of the evaluation, formulation of a comprehensive radiation protection strategy for NORM in Japan, and clarification of policies and procedures on sharing and disseminating relevant information to the public.
5 0 0 0 OA 1954 年に日本各地で観測された雨水中全β放射能の再検討
- 著者
- 辻村 憲雄
- 出版者
- 一般社団法人日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.54, no.1, pp.40-44, 2019-04-18 (Released:2019-09-03)
- 参考文献数
- 21
Rainwater containing radioactive materials originating from the USA’s nuclear weapon test conducted at Bikini Atoll was observed throughout Japan in 1954. It has been reported that the maximum gross beta activity observed at that time in Kyoto was 523 pCi/mL (19,000 Bq/L). This measurement, however, focused on the gross beta activity contained in a small amount of rain sampled at the beginning of rainfall, which is different from present observations that are based on the average gross beta activity contained in rain collected during a 24-h period. As a result of reviewing and converting the 1954 data to be equivalent to current measurement, the maximum value was reduced to 50 pCi/mL (1,800 Bq/L), with a resultant surface deposition density of 310 mCi/km2 (11,000 MBq/km2). These values are well below 1/10 of the past maximum observed a few days after China’s fifth nuclear weapon test in 1966.
- 著者
- Hidehito NAKAMURA Yoshiyuki SHIRAKAWA Hisashi KITAMURA Nobuhiro SATO Sentaro TAKAHASHI
- 出版者
- 一般社団法人日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.49, no.2, pp.98-101, 2014 (Released:2015-05-21)
- 参考文献数
- 25
- 被引用文献数
- 7 9
The enormous area of damage to Japan's Fukushima Daiichi nuclear power plant requires radiation detectors with robust base substrates to monitor high-dose-rate environmental radiation with long-term stability. Undoped aromatic ring polymers have considerable potential as base substrates in radiation detection. Here, we characterise polycarbonate (PC), which has excellent transparency, shock, radiation, and weather resistance, heat tolerance, and anti-abrasion qualities. It has a density of 1.20 g/cm3, an excitation maximum of 310 nm, and short-wavelength emission with a maximum at 350-nm. By taking into account its emission spectrum, we determined an effective refractive index of 1.64. PC has a light yield that is 0.67 times that of undoped poly (ethylene terephthalate). These results reveal that readily available PC is an effective base substrate for use in large-area radiation detectors for the nuclear power plant recovery process.
1 0 0 0 OA 放射線防護に関する主な国際組織の活動と相互の関係
- 著者
- 保田 浩志 賞雅 朝子 飯本 武志
- 出版者
- 一般社団法人日本保健物理学会
- 雑誌
- 保健物理 (ISSN:03676110)
- 巻号頁・発行日
- vol.57, no.1, pp.30-35, 2022-03-31 (Released:2022-05-26)
- 参考文献数
- 3
In addition to the International Commission on Radiological Protection (ICRP), there are several international organizations that are engaged in activities related to radiological protection. This article briefly reviews the aims and major activities of and interrelationships between those organizations, followed by opinions about how Japanese experts should contribute to those activities.
