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Takimoto, Misaki; Yamazaki, Takumi; Takada, Chie
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no abstracts in English
Kono, Takahiko; Hattori, Takatoshi*; Yokoyama, Sumi*; Nakano, Hironori*; Sato, Noriko*; Kudo, Hiromi*; Nomura, Naoki*; Sakoda, Akihiro; Naito, Wataru*; Kuroda, Yujiro*; et al.
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no abstracts in English
Kono, Takahiko; Blinova, O.*; Rozmaric, M.*
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Okuyama, Shun
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Uchida, Masahiro; Yamazaki, Takumi; Takada, Chie; Tsujimura, Norio
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Yoshida, Tadayoshi; Isozaki, Kohei; Tamura, Ken; Nakagawa, Takahiro; Kawasaki, Takashi; Momose, Takumaro
no journal, ,
no abstracts in English
Nakajima, Junya; Yamada, Katsunori; Hasegawa, Rie; Umeda, Masayuki; Seki, Masakazu; Muto, Yasushi; Sawahata, Katsunori
no journal, ,
STACY (Static Experiment Critical Facility) has been under remodeling work. During the demolition work of the previous model of STACY, we conducted radiation management for both internal exposure and external exposure taking the characteristics of the previous model into consideration. As a result, any contamination and internal exposure of the all workers was detected, and external exposure of the all workers were less than the detection limit.
Takahashi, Akina; Sakashita, Satoshi; Shiba, Kozo; Yoshida, Tadayoshi
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Sakoda, Akihiro; Nomura, Naoki*; Naito, Wataru*; Kono, Takahiko; Kuroda, Yujiro*; Yoshida, Hiroko*
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Rn, 
Pb and 
Be concentrations in Ningyo-toge, Okayama prefectureSakoda, Akihiro; Tanaka, Hiroshi; Kanzaki, Norie
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no abstracts in English
Takahashi, Fumiaki; Manabe, Kentaro; Sato, Kaoru; Tokashiki, Yuji*
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If national radiation safety regulations are revised by adapting the concept of the ICRP 2007 Recommendations, the protection standard values are also reviewed for radiation exposure. Thus, JAEA has developed an internal dosimetry code based on the ICRP 2007 Recommendations since FY 2017. Two functions are to be incorporated to the codes. One is "dose coefficient calculation function" that is used to verify the new dose coefficients by ICRP and the other is "nuclide intake estimation function" for internal dosimetry monitoring. In addition, we have developed GUI to set up calculation condition and functions to indicate results. In the dose coefficient calculation function, a user can set up internal dosimetry model based upon the 1990 recommendation to investigate the influencing factors on a difference between the old and new dose coefficients. In addition, results such as in-vivo radioactivity are also displayed with a graph in the nuclide intake estimation function. We will report an overview of the beta version of the code that integrates the two functions.
Saito, Tatsuo
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From 2017 June to 2019 March, our task group of radiation protection for wastes with natural radioactive nuclides studied issues about clearance and disposal of uranium bearing waste, concerning its billions-year halflife and build-up its dose with its progenies generation. Here we report about important of our issues. The first issue is uncertainty of long term safety assessment of near surface disposal. We proposed to introduce qualitative assessment for over several 10,000 year-long term safety assessment, difficult to show its dose, because of uncertainty of the assessment, but to show safety inclenation based on reliable quantitative assessment for 1,000 or 10,000 year. The second issue is radon generation of several thousands years after disposal. It is difficult to reduce radon with disposal facility design after several ten thousand years. We propose to discuss for safety standard for radon, such as clearance level for radon assessment, or reference level for existence situation for the sum of radon from natural soil and disposal wastes. Regarding the disposal of uranium waste from the viewpoint of "intergenerational ethics", the burden and responsibility to be taken regarding the balance of the burden between the future generation and the current generation could not be organized.
Sakashita, Satoshi; Takahashi, Akina; Yoshida, Tadayoshi; Shiba, Kozo
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Oba, Takashi*; Ishikawa, Tetsuo*; Nagai, Haruyasu; Tokonami, Shinji*; Hasegawa, Arifumi*; Suzuki, Gen*
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Sato, Kaoru; Furuta, Takuya; Takahashi, Fumiaki
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We previously constructed average adult Japanese voxel phantoms (male: JM-103, female: JF-103) and others with various body sizes for application to dose assessment against persons with Japanese physiques. Generally, voxel phantom is not practical tool for dose assessment under various posture conditions, because of long construction term and difficulty of organ deformation. Thus, we are now constructing adult Japanese polygon male (JPM) and female (JPF) phantoms by modifying JM-103 and JF-103. In construction of JPM and JPF, the following processing were performed: (1) extraction of organ surface from JM-103 and JF-103, (2) smoothing organ surface, (3) adjustment of mass, shape and location, (4) multilayering of constructed polygon. Masses of most organs in JPM or JPF agreed with adult Japanese averages within 5%. In future, we will develop the limb operation technique for JPM and JPF. JPM and JPF with the new technique will be used for dose assessment against persons with various postures.
Tamura, Ken; Isozaki, Kohei; Yoshida, Tadayoshi; Nakagawa, Takahiro; Kawasaki, Takashi; Momose, Takumaro
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Isozaki, Kohei; Tamura, Ken; Yoshida, Tadayoshi; Nakagawa, Takahiro; Kawasaki, Takashi; Momose, Takumaro
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Satoh, Daiki; Takahashi, Fumiaki
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In the radiation-protection system proposed by the International Commission on Radiological Protection (ICRP) and the International Commission on Radiation Units and Measurements (ICRU), the protection quantities, which are linked to a risk of radiation exposure and are unmeasurable, are assessed by measuring the operational quantities. Hence, the relationship between the protection quantities and the operational quantities is important for a rational radiation protection. Recently, the ICRP is developing the reference phantoms of newborn, 1-year old, 5-year old, 10-year old, and 15-year old children as well as the existing adult reference phantoms for computing effective doses as the protection quantities. In addition, the joint group of the ICRP and ICRU proposed the new operational quantities to replace the existing ones. In this study, we investigated the relationship between the age-dependent effective doses as the protection quantities and the ambient dose as the new operational quantities using the radiation transport code PHITS under the ideal photon exposure conditions defined by the ICRP/ICRU and the environmental exposure condition observed in the Fukushima. Under the ideal exposure conditions, the values of the ambient dose were agreed within 5% with those of the age-dependent effective dose above 0.05 MeV. In the environmental photon fields, we concluded that the effective dose of the public can be assessed by measuring the ambient dose.
Kato, Saori; Kasugai, Yoshimi; Saito, Fumihiro; Masukawa, Fumihiro; Numajiri, Masaharu*; Nakamura, Hajime*; Yamazaki, Hirohito*; Saito, Kiwamu*; Fujiwara, Kazuya*
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Otsu, Saori; Tsubota, Yoichi; Uchida, Masahiro; Nakagawa, Takahiro; Kawasaki, Takashi
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no abstracts in English