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Noda, Mayuko; Kometani, Tatsunari; Suzuki, Takehiko
no journal, ,
no abstracts in English
Kim, M.; Malins, A.; Yoshimura, Kazuya; Machida, Masahiko; Saito, Kimiaki; Yoshida, Toru*; Yanagi, Hideaki*; Hasegawa, Yukihiro*; Yoshida, Hiroko*
no journal, ,
no abstracts in English
Satoh, Daiki; Sato, Tatsuhiko; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Recently, International Commission on Radiological Protection (ICRP) released the mesh-type reference computational phantoms of adult male and female, whose resolutions are much higher than those of conventional voxel phantoms. In addition, the mesh-type pediatric computational phantoms of newborn, 1-year-old, 5-year-old, 10-year-old, and 15-year-old male and female were constructed by a research group of Hanyang University, Korea, and became available. In this study, we analyzed age-dependent tissue and organ absorbed doses using those mesh-type phantoms for external neutron exposures. The phantoms were incorporated into a general-purpose radiation transport code PHITS, and irradiated by neutrons at 68 energy points from 10
to 10
MeV under 6 ideal irradiation conditions. The simulation results say that the thermal-neutron capture reaction of hydrogen plays an important role below approximately 0.1 MeV and the doses of adults is higher than those of pediatrics because larger body size leads to generating more thermalized neutrons. Above 0.1 MeV, recoil protons from elastic collision of hydrogen are dominant contributor to the doses and doses of pediatrics become larger than those of adults because those protons can reach to deep organs of pediatrics.
Manabe, Kentaro; Sato, Kaoru; Takahashi, Fumiaki
no journal, ,
Japan Atomic Energy Agency (JAEA) has developed an internal dose calculation code in accordance with the 2007 Recommendations of the International Commission on Radiological Protection in a four-year project from FY 2017 to FY 2020 entrusted by the Nuclear Regulation Authority. The code has two major functions. One is a function calculating dose coefficients, which are committed effective doses per intake of radioactivity: The other is a function estimating an intake of activity based on monitoring data. The graphical user interface of the code integrates the two functions and provides easy operation. A new project has been started from FY 2021 to advance the code by implementing models and data to be published in the future, to establish a system for distribution of the code, and to promote usage of the code. We present the features and the future developments of the code.
Hashimoto, Hiroki*; Yamada, Ryohei; Yamaguchi, Kanna*; Sasaki, Koichi*; Tamakuma, Yuki*; Hosoda, Masahiro*; Akata, Naofumi*; Tokonami, Shinji*
no journal, ,
no abstracts in English
Takahashi, Fumiaki; Sato, Kaoru; Satoh, Daiki
no journal, ,
In 2010, the International Commission on Radiological Protection (ICRP) indicated that the current operational quantities would underestimate effective doses based upon ICRP 2007 Recommendations. The International Commission on Radiation Unit and Measurement (ICRU) published new operational quantities in 2020. It can be required to use radiations instruments and dosimeters that correspond to the current operation quantities, even after Japanese standards for radiation safety are revised by taking account for ICRP 2007 Recommendations. Thus, we have analyzed relationships between current operational quantities and effective doses (current and new) for external neutron exposure by using spectra compiled in IAEA report. It is cleared that the current operational quantities can safely estimate the new effective dose. In addition, ratio of the new effective dose to the current operational quantity strongly depends on energy spectra in neutron fields.
Sato, Kaoru; Furuta, Takuya; Takahashi, Fumiaki
no journal, ,
We are now developing adult Japanese polygon human models (male: JPM and female: JPF) for the purposes of dose assessment of Japanese. At the 2nd joint annual research meeting of JHPS and JRSM, overviews of development of these human models were presented. Thereafter, we performed the improving of the posture change functions and averaging of organ masses and body sizes. In this presentation, we will introduce and explain about the characteristics of posture change functions and physiques of JPM and JPF. In addition, we will show test calculation results of organ doses under various postures.
Hayashi, Masateru*; Makita, Taisuke*; Azuma, Tetsushi*; Sasano, Makoto*; Yoshida, Hiroko*; Tsuda, Shuichi
no journal, ,
Evaluation of dose rates of artificial nuclides is of importance to make a decision on return of residents to their hometown contaminated by the Fukushima Dai-ichi Nuclear Power Plant accident. This study applies an unfolding method to measured data by a NaI(Tl) detector in/outside houses, and obtained gamma-ray energy spectra. We calculated ratios of dose rate from natural nuclides such as 40K and Uran-Thorium series to those of artificial nuclides. It was found that the ratios are almost constant, given that no artificial nuclide exists. This means a possibility that dose rates of artificial nuclides can be precisely estimated by subtracting dose rates of natural nuclides.
BaTsuji, Tomoya; Yoshitomi, Hiroshi; Kowatari, Munehiko*; Tanimura, Yoshihiko
no journal, ,
no abstracts in English
Takada, Chie; Nakano, Masanao; Munakata, Masahiro; Yoshida, Tadayoshi; Yokosuka, Yoshiyuki; Yamada, Junya; Maeda, Eita; Watanabe, Yuki; Tomioka, Akifumi; Momose, Takumaro
no journal, ,
no abstracts in English
Kashimura, Keita; Kawasaki, Masatsugu; Okura, Takehisa
no journal, ,
In nuclear emergency response involving atmospheric release, the supplementary reference materials of the Nuclear Emergency Response Guideline require dust monitor to monitor radiation situation in the environment to be able to detect facility-induced releases of about 5 Bq/m
for detecting unexpected releases earlier, and to determine the spatial distribution of radioactive materials in the air during emergencies, the difference in the gross beta activity concentration measured every 10 minutes is used. In this study, method of monitoring radioactive plume by dust monitor was investigated, and it was confirmed that the method can discriminate facility-induced releases of about 5 Bq/ m against variation of natural radionuclides. Furthermore, capability of the dust monitor corresponding to radioactive plume was confirmed. According to the time series comparison between the gross beta radioactivity concentration measured by the dust monitor and the radioactive concentration analyzed from gamma-ray emitted nuclides in the air following the Fukushima Daiichi Nuclear Power Plant accident (1F accident), a good correlation was observed and it was found that the dust monitor responded accurately to the fluctuation of the concentration in the radioactive plume. And it was confirmed that it was possible to discriminate the incremental difference in gross beta radioactivity caused by the facility of about 5 Bq/ m against the slight increase in concentration caused by the 1F accident.
Wada, Rina; Nakayama, Naoto; Nohara, Naofumi; Saito, Kei
no journal, ,
no abstracts in English
Yoshida, Hiroko*; Nomura, Naoki*; Kono, Takahiko; Sakoda, Akihiro; Kuroda, Yujiro*; Naito, Wataru*; Hirota, Seiko*; Kudo, Shinichi*; Takahara, Shogo; Etani, Reo*; et al.
no journal, ,
The WG has translated the "Practical Guidance for Engagement with the Public on Radiation and Risk" ("IRPA Guidance") issued by the International Radiation Protection Association ("IRPA") to its member societies in 2020. "Practical Guidance for Engagement with the Public on Radiation and Risk" (hereinafter referred to as "IRPA Guidance") published by the International Radiological Protection Association (hereinafter referred to as "IRPA") in 2020 for its member societies, and to provide the information to radiation protection experts and other interested.
Yoshida, Hiroko*; Nomura, Naoki*; Kono, Takahiko; Sakoda, Akihiro; Kuroda, Yujiro*; Naito, Wataru*; Hirota, Seiko*; Kudo, Shinichi*; Kawaguchi, Isao*; Etani, Reo*; et al.
no journal, ,
The WG has translated the "Practical Guidance for Engagement with the Public on Radiation and Risk" ("IRPA Guidance") issued by the International Radiation Protection Association ("IRPA") to its member societies in 2020. "The content of the IRPA guidance was presented at a symposium organized by the Health Physics Society of Japan in June 2020. The content of the IRPA guidance was presented at the Health Physics Society planning symposium held in June 2020, where many experts attended and provided feedback. In this planning session, we will focus on public engagement and related specific examples and situations related to public engagement.
Yasuda, Hiroshi*; Saito, Tatsuo; Fumoto, Hiromichi*; Kasai, Atsushi*; Shimo, Michikuni*; Sugawara, Shinetsu*; Tsuchida, Shoji*; Furuta, Sadaaki*
no journal, ,
Contaminated with naturally occurring radionuclides uranium and its progeny nuclides, "uranium bearing wastes" have very long half-life to decay its radioactivity, which can be hundreds of thousands of years, and have risk to impose a considerable burden on future generations. Based on this, the authors considered that it is important to consider not only from the viewpoint of science and engineering as has been done so far, but also from the viewpoint of humanities and social sciences such as philosophy and history. Therefore, in 2020, the Health Physics Society of Japan established the "the Expert Panel on Management of NORM-Containing Wastes Investigated through the Perspective of Humanities and Social Sciences, and related fields". In this session, we will report on the history and future outlook of our activities so far.
Hosoda, Masahiro*; Saito, Kimiaki; Mikami, Satoshi; Sanada, Tetsuya*; Omori, Yasutaka*; Takeda, Hikaru*; Yamada, Takahiro*; Hirao, Shigekazu*; Tani, Kotaro*; Orita, Makiko*; et al.
no journal, ,
no abstracts in English
Sakoda, Akihiro; Tanaka, Hiroshi; Ishimori, Yuu
no journal, ,
Ningyo-toge Environmental Engineering Center made the soil capping at part of the uranium mill tailings pond and then has been accumulating a variety of measurement data for consideration of its effectiveness. We have presented some data on the depth profile of soil radon gas concentrations measured from April to December 2015, at the annual meeting of Japan Health Physics Society in 2016. The soil radon measurement has been performed to now with modification of measurement methods. The present talk reports the results of soil radon measurements for three years (2018 to 2020) and numerical simulations.
Katengeza, E.*; Sanada, Yukihisa; Ochi, Kotaro; Iimoto, Takeshi*
no journal, ,
The calibration factor (CF) was determined by comparing the counting rate obtained by plastic scintillation fibers (PSF) with the average radiocesium (RCs) concentration in the top 10 cm of sediment core samples in previous study. The systematic biases and measurement uncertainty of estimated RCs concentration were evaluated by comparing against the RCs concentration in sampled sediment cores averaged over depths, ranging from 5 cm to 30 cm in 5 cm increments. When the calibration depth is 10 and 15 cm, the normalized mean square and relative deviation of PSF-derived RCs concentration against RCs concentration in sampled sediment were comparable. Thus, it may be necessary to revise calibration depth in order to sustainably optimize radiocesium concentration measurements by the PSF technique.
Na and 
Be depositions in Tsuruga cityYoshida, Keisuke; Kato, Shingo; Inoue, Mutsuo*; Ishizuka, Akihiro; Okuyama, Shinichi
no journal, ,
Na is observed for environmental monitoring of Monju fast breeder reactor because Monju reactor contains Na in primary coolant. But Na is produced in upper atmosphere, therefore, Na is detected in assembled deposition sample. To increase accuracy of environmental monitoring, it is necessary to understand transport and supply process of Na and Be depositions from high latitude region where a lot of Na is produced. We collect deposition samples at Tsuruga city to measure Na and collect Be deposition data in 5 sites in Fukui prefecture and Ishikawa prefecture. Because Na and Be shows good correlation, Na have same behavior with Be. Be deposition is maximum at Kanazawa city and minimum at Shika town, but Be deposition is maximum in Winter season at all sites. Be deposition and precipitation shows correlation. From the above, Winter monsoon transport Be and Na from high latitude region and precipitation provide these nuclides to ground surface at Tsuruga city. The deference of Be deposition in Winter season is likely owing to height of mountain and distance of sampling sites.
Morishita, Yuki
no journal, ,
Alpha, beta, gamma radioactive contamination exist at the site of decommissioning of nuclear facilities such as the Fukushima Daiichi Nuclear Power Station. In order to accurately detect these nuclides, we have developed a new small alpha/beta/gamma-ray discrimination type detector.