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Kaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Takahashi, Hiroyuki*
Journal of Nuclear Science and Technology, 59(8), p.983 - 992, 2022/08
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)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
Kaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*
Nuclear Instruments and Methods in Physics Research A, 1010, p.165544_1 - 165544_9, 2021/09
Times Cited Count:0 Percentile:0.00(Instruments & Instrumentation)The number of nuclear facilities being decommissioned has been increasing worldwide, in particular following the accident of the Tokyo Electric Power Company Holdings' Fukushima Daiichi Nuclear Power Station in 2011. In these nuclear facilities, proper management of radioactive materials is required. Then, A -ray spectrometer with four segmentations using small volume CeBr scintillators with a dimension of was developed. The four scintillators were coupled to a multi-anode photomultiplier tube specific to intense radiation fields. We performed the -ray exposure study under Cs and Co radiation fields. Under the Cs radiation field, the relative energy resolution at 1375 mSv/h was the relative energy resolution at 1375 mSv/h was 9.20.05%, 8.00.08%, 8.00.03%, and 9.00.04% for the four channels, respectively.
Kaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.
Nuclear Instruments and Methods in Physics Research A, 988, p.164900_1 - 164900_8, 2021/02
Times Cited Count:11 Percentile:83.42(Instruments & Instrumentation)An increasing number of nuclear facilities have been decommissioned worldwide following the 2011 accident of the TEPCO' Fukushima Daiichi Nuclear Power Station. During the decommissioning, radioactive materials have to be retrieved under proper management. In this study, a small cubic CeBr spectrometer with dimensions of 5 mm 5 mm 5 mm was manufactured to perform -ray spectroscopy under intense -ray fields. Furthermore, thanks to a fast digital process unit and a customized photomultiplier, the device could perform -ray spectroscopy at dose rates of over 1 Sv/h. The energy resolution (FWHM) at 662 keV ranged from 4.4% at 22 mSv/h to 5.2% at 1407 mSv/h for a Cs radiation field. Correspondingly, at 1333 keV, it ranged from 3.1% at 26 mSv/h to 4.2% at 2221 mSv/h for a Co radiation field, which suggested to realize -ray assessment of Cs, Cs, Co, and Eu at dose rates of over 1 Sv/h.
Yokoyama, Sumi*; Hamada, Nobuyuki*; Hayashida, Toshiyuki*; Tsujimura, Norio; Tatsuzaki, Hideo*; Kurosawa, Tadahiro*; Nabatame, Kuniaki*; Oguchi, Hiroyuki*; Ono, Kazuko*; Kawaura, Chiyo*; et al.
Journal of Radiological Protection, 37(3), p.659 - 683, 2017/09
Times Cited Count:15 Percentile:79.81(Environmental Sciences)Since the International Commission on Radiological Protection recommended reducing the occupational equivalent dose limit for the lens of the eye in 2011, there have been extensive discussions in various countries. This paper reviews the current situations in radiation protection of the ocular lens and the discussions on the potential impact of the new lens dose limit in Japan. Topics include historical changes to the lens dose limit, the current situations in occupational lens exposures (e.g., in medical workers, nuclear workers, and Fukushima nuclear power plant workers) and measurements, and the current status of biological studies and epidemiological studies on radiation cataracts. Our focus is on the situations in Japan, but we believe such information sharing will be useful in many other countries.
Akahane, Keiichi*; Iimoto, Takeshi*; Ichiji, Takeshi*; Iwai, Satoshi*; Oguchi, Hiroyuki*; Ono, Kazuko*; Kawaura, Chiyo*; Kurosawa, Tadahiro*; Tatsuzaki, Hideo*; Tsujimura, Norio; et al.
Hoken Butsuri, 50(4), p.257 - 261, 2015/12
In a mixed field of photon and beta radiations, the same dose assigned to skin is normally assigned to the dose to the lens of the eye as a conservative estimate of H(3). In exceptional cases that a very high beta dose might be imparted of the same order with the dose limit, however, the conservatively biased dose must be too limiting, and thereby an accurate estimate of beta (3) is desirable. This article presents a practical proposal of when and how the dosimetry of beta (3) should be made.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.
JAEA-Research 2014-030, 457 Pages, 2015/03
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.
Satoh, Daiki; Kurosawa, Tadahiro*; Sato, Tatsuhiko; Endo, Akira; Takada, Masashi*; Iwase, Hiroshi*; Nakamura, Takashi; Niita, Koji*
Nuclear Instruments and Methods in Physics Research A, 583(2-3), p.507 - 515, 2007/12
Times Cited Count:27 Percentile:84.38(Instruments & Instrumentation)Previously-published data of secondary neutron spectra from thick targets of C, Al, Cu and Pb bombarded with heavy ions from He to Xe are revised by using a new set of neutron-detection efficiency values for a liquid organic scintillator calculated with SCINFUL-QMD. Additional data have been measured for bombardment of C target by 400-MeV/nucleon C ions and 800 MeV/nucleon Si-ions. The set of spectra are compared with the calculation results using a Monte-Carlo heavy-ion transport code, PHITS. It was found that PHITS is able to reproduce the secondary neutron spectra in a wide neutron-energy regime.
Yoshikawa, Hideki; Shibata, Masahiro; Sasamoto, Hiroshi; Iijima, Kazuki; Sato, Haruo; Kitamura, Akira; Ishidera, Takamitsu; Fujiwara, Kenso; Kurosawa, Susumu; Xia, X.; et al.
Hoshasei Haikibutsu Anzen Kenkyu Nenji Keikaku (Heisei-13-NendoHeisei-17-Nendo) Kenkyu Seika Hokokushu, p.153 - 170, 2006/03
no abstracts in English
Tanaka, Susumu; Nakashima, Hiroshi; Sakamoto, Yukio; Nakane, Yoshihiro; Meigo, Shinichiro; Tanaka, Shunichi; Nakamura, Takashi*; Takada, Masashi*; Kurosawa, Tadahiro*; Hirayama, Hideo*; et al.
Health Physics, 81(4), p.406 - 418, 2001/10
Times Cited Count:5 Percentile:38.62(Environmental Sciences)no abstracts in English
Nakashima, Hiroshi; Masumura, Tomomi*; Tanaka, Susumu; Sakamoto, Yukio; Takada, Hiroshi; Tanaka, Shunichi; Nakane, Yoshihiro; Meigo, Shinichiro; Nakamura, Takashi*; Kurosawa, Tadahiro*; et al.
Journal of Nuclear Science and Technology, 37(Suppl.1), p.192 - 196, 2000/03
no abstracts in English
Nakashima, Hiroshi; Masumura, Tomomi*; Tanaka, Susumu; Sakamoto, Yukio; Tanaka, Shunichi; Nakane, Yoshihiro; Meigo, Shinichiro; Nakamura, Takashi*; Kurosawa, Tadahiro*; Hirayama, Hideo*; et al.
Journal of Nuclear Science and Technology, 37(Suppl.1), p.197 - 201, 2000/03
no abstracts in English
Nunomiya, Tomoya*; Kim, E.*; Kurosawa, Tadahiro*; Taniguchi, Shingo*; Nakamura, Takashi*; Tsujimura, Norio; Momose, Takumaro; Shinohara, Kunihiko
JNC TY8400 99-007, 29 Pages, 1999/03
None
; Nakane, Yoshihiro; Sakamoto, Yukio; Nakashima, Hiroshi; Meigo, Shinichiro; Tanaka, Shunichi; Kurosawa, Tadahiro*; Nakamura, Takashi*; Nakao, Noriaki*; Hirayama, Hideo*; et al.
Proc. of 1998 ANS Radiat. Protection and Shielding Division Topical Conf. Technol. for the New Century, 2, p.164 - 169, 1998/00
no abstracts in English
Tanaka, Susumu; Nakashima, Hiroshi; Nakane, Yoshihiro; Sakamoto, Yukio; Meigo, Shinichiro; Tanaka, Shunichi; Takada, Masashi*; Kurosawa, Tadahiro*; Nakamura, Takashi*; Nakao, Noriaki*; et al.
Genshikaku Kenkyu, 41(3), p.101 - 112, 1996/06
no abstracts in English
Sakamoto, Yukio; Tanaka, Susumu; ; Nakane, Yoshihiro; Meigo, Shinichiro; Takada, Hiroshi; Tanaka, Shunichi; Takada, M.*; Kurosawa, Tadahiro*; Nakamura, Takashi*; et al.
Genshikaku Kenkyu, 41(3), p.95 - 99, 1996/06
no abstracts in English
Kaburagi, Masaaki; Takahashi, Hiroyuki*; Shimazoe, Kenji*; Kurosawa, Tadahiro*; Kato, Masahiro*
no journal, ,
no abstracts in English
Satoh, Daiki; Kurosawa, Tadahiro*; Sato, Tatsuhiko; Endo, Akira; Takada, Masashi*; Iwase, Hiroshi*; Nakamura, Takashi; Niita, Koji*
no journal, ,
Previously-published data of secondary neutron spectra from thick targets of C, Al, Cu and Pb bombarded with heavy ions from He to Xe are revised by using a new set of neutron-detection efficiency values for a liquid organic scintillator calculated with SCINFUL-QMD. Additional data have been measured for bombardment of C target by 400-MeV/nucleon C ions and 800 MeV/nucleon Si-ions. The set of spectra are compared with the calculation results using a Monte-Carlo heavy-ion transport code, PHITS. It was found that PHITS is able to reproduce the secondary neutron spectra in a wide neutron-energy regime.
Kaburagi, Masaaki; Shimazoe, Kenji*; Kato, Masahiro*; Kurosawa, Tadahiro*; Kamada, Kei*; Kim, K. J.*; Yoshino, Masao*; Shoji, Yasuhiro*; Yoshikawa, Akira*; Takahashi, Hiroyuki*; et al.
no journal, ,
The retrieval of nuclear fuel debris will be started at Tokyo Electrical Power Company Holdings' Fukushima Daiichi Nuclear Power Station. Because of high dose-rate fields on the surface of nuclear fuel debris and these inhomogeneous elements, non-destructive analysis is required during the retrieval. Here, it is presented that a -ray spectrometry system specific to high dose-rate fields was developed and its performance under intense -ray fields was evaluated for the retrieval of nuclear fuel debris.
Kaburagi, Masaaki; Shimazoe, Kenji*; Kurosawa, Tadahiro*; Kato, Masahiro*; Takahashi, Hiroyuki*
no journal, ,
no abstracts in English