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Shioya, Satoshi; Nakagawa, Takahiro; Yamazaki, Takumi; Tachihara, Joji; Shuji, Yoshiyuki; Kikuno, Hiroshi
no journal, ,
In order to reduce the workload and improve the safety (i.e., prevention of internal exposure) of workers at Plutonium handling facilities, etc., JAEA has introduced a new Powered Air Purifying Respirator (PAPR) full-face mask as respiratory protective equipment. In introducing this mask, we conducted a leakage test in correspondence with Japanese Industrial Standards (JIS). In the leakage test, an examinee person wearing the mask entered an airlock and performed a prescribed action (e.g., stepping up and down on a stepladder, etc.) while the number concentration of NaCl test particles in/out of the mask was measured. Leakage rates were calculated for the results of 10 examinees. The test results showed that the leakage rate of this mask was 
0.01% (corresponding to the protection factor of 
10000) even when the electric fan was stopped, confirming that the mask remained high protection capability.
Po-gross alpha countsYamada, Ryohei; Hashimoto, Hiroki*; Tamakuma, Yuki*; Omori, Yasutaka*; Hosoda, Masahiro*; Akata, Naofumi*; Uchiyama, Rei; Nakada, Akira; Endo, Michitaka*; Imajo, Yusuke*; et al.
no journal, ,
no abstracts in English
Takahashi, Fumiaki; Manabe, Kentaro
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If the 2007 Recommendations of International Commission on Radiological Protection (ICRP) are incorporated to radiation regulations in Japan, the regulatory standard values are also to be revised for exposure dose assessment. Thus, we have proceeded surveys of exposure dose evaluation data based on the 2007 Recommendations. New effective dose conversion coefficients are published by expanding radiation types and energies beyond the current regulations in Japan for external exposure dose assessments. In addition, new effective dose coefficients for internal dosimetry due to occupational exposure have been given with radioisotope types revised by reflecting the latest scientific knowledge. Here, it might be essential to consider whether to adopt these data with consideration of exposure situations at radiation facilities. In addition, we should take care of discussions in ICRP for the general recommendations in future.
Yoshitomi, Hiroshi; Nishino, Sho; Tsuji, Tomoya; Fukami, Tomoyo; Takamine, Jun; Umino, Kazushige*; Murayama, Takashi; Tanimura, Yoshihiko
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no abstracts in English
Saito, Tatsuo; Sugaya, Toshikatsu; Sakai, Akihiro; Kamei, Gento
no journal, ,
In Japan, low-level radioactive wastes generated from research institutes, universities and medical institutions are continuously stored without being buried. Therefore, the Japan Atomic Energy Agency (JAEA) has been an implementation body of the burial project of the radioactive wastes from research facilities. In this report, the characteristics of the wastes and the conceptional design of the JAEA burial facilities are introduced, and the current status of the study on the radioactivity concentrations corresponding to dose criterion for trench disposal and pit disposal is also presented.
Satoh, Daiki; Nakayama, Hiromasa; Onodera, Naoyuki
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no abstracts in English
Satoh, Daiki; Sasaki, Michiya*; Furukawa, Kyoji*; Shimada, Kazumasa; Kudo, Shinichi*; Takahara, Shogo; Takagi, Shunji*; Kai, Michiaki*
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no abstracts in English
Sato, Rina; Yoshimura, Kazuya; Sanada, Yukihisa; Yajima, Kazuaki*; Aono, Tatsuo*
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no abstracts in English
Sasaki, Michiya*; Furukawa, Kyoji*; Satoh, Daiki; Shimada, Kazumasa; Kudo, Shinichi*; Takahara, Shogo; Takagi, Shunji*; Kai, Michiaki*
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no abstracts in English
Kai, Michiaki*; Shimada, Kazumasa; Kudo, Shinichi*; Furukawa, Kyoji*; Satoh, Daiki; Takahara, Shogo; Takagi, Shunji*; Sasaki, Michiya*
no journal, ,
This presentation is the third in a series of three presentations on the results of the "Expert Group on the Development of Cancer Risk Estimation Codes Associated with Radiation Exposure" established by the Japan Health Physics Society, which examines the parameters employed in the codes and the calculation results, and summarizes the future prospects of the codes. In order to calculate cumulative excess risk (CER) as a measure of lifetime risk with confidence intervals, a variance-covariance matrix for the parameters of the risk model is required. However, in a study conducted by the Radiation Effects Research Foundation using the regression analysis program Epicure on large-scale epidemiological data from A-bomb survivors, the variance-covariance matrix was not disclosed. Therefore, in this study, we independently derived parameters and covariance matrices using a generalized linear model (GLM) and confirmed that the parameter values agreed well with the Epicure results. The CERs calculated using the derived parameters and covariance matrices were compared with those calculated by the U.S. code RadRAT. Although a simple comparison is not possible due to the different population baselines of the two codes, they were found to be in general agreement. The developed code is expected to contribute to the discussion of influence factors and uncertainty in risk assessment.
Yoshida, Hiroko*; Kim, M.; Malins, A.; Machida, Masahiko
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no abstracts in English
Koh, S.*; Hirao, Shigekazu*; Torii, Tatsuo; Sanada, Yukihisa
no journal, ,
Studies of atmospheric processes frequently make use of Rn-222, an inert radioactive gas with a half-life of 3.82 days widely found in the atmosphere. There are few measurements of Rn-222 at high altitudes, and there is limited knowledge of its regional behaviour. Rn-222 decay products in the air interfere with aerial radiological survey (ARS) carried out since the Fukushima Daiichi NPP accident intended to quantify the spatial and temporal dispersion of surface radiation from Fukushima derived radionuclides. The purpose of this study is to investigate the feasibility of using ARS data to estimate the concentration to Rn-222 in the atmosphere.
Yasuda, Hiroshi*; Fumoto, Hiromichi*; Saito, Tatsuo
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This project aims to discuss whether the approach of presenting exposure of future generations to radionuclides with long half-lives as potential exposure is compatible with the current concept of geological disposal, by extending the target from uranium waste to radioactive waste including intermediate and high level radioactive waste. The issues and the matters that should be presented and provided to the concerned parties, including future generations, are to be discussed extensively. The discussion will then organize ideas concerning issues such as how much concentration of waste can be disposed of, at what depth and scale, and what will be required when it is lost in the future, and will incorporate not only the science and engineering approach, but also the humanities and social science approach that the proponents have been considering, in order to provide a broader The proposers will discuss from a broader perspective, incorporating not only the science and engineering approach but also the humanities and social science approach that they have been considering. The status of these activities will be explained.
Sr/Y and 
Cs using a liquid light guide Cerenkov counterTerasaka, Yuta; Uritani, Akira*
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no abstracts in English
Sakoda, Akihiro; Hasan, Md. M.*; Iimoto, Takeshi*
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Tsuji, Tomoya; Yoshitomi, Hiroshi; Tanimura, Yoshihiko
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no abstracts in English
Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Nishino, Sho; Tsuji, Tomoya; Fukami, Tomoyo; Takamine, Jun
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no abstracts in English
Sakashita, Koichi; Kasugai, Yoshimi; Harada, Masahide; Seki, Kazunari; Sato, Koichi; Kato, Saori; Arakawa, Yuto
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no abstracts in English
Maeda, Eita; Hashimoto, Makoto; Nohara, Naofumi; Muto, Yasunobu; Yamada, Junya; Hamaguchi, Takumi; Inoue, Yuki
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no abstracts in English
Saito, Fumihiro; Kasugai, Yoshimi; Seki, Kazunari; Nakane, Yoshihiro; Tani, Norio; Sato, Koichi; Yamazaki, Hirohito*; Bessho, Kotaro; Numajiri, Masaharu
no journal, ,
no abstracts in English
Kato, Shingo; Yoshida, Keisuke; Inoue, Mutsuo*; Yamashita, Masahiro; Okuyama, Shinichi; Ishimori, Yuu
no journal, ,
no abstracts in English