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Journal Articles

Integrating radiation protection criteria for radioactive waste management into remediation procedures in existing exposure situations after a nuclear accident

Sugiyama, Daisuke*; Kimura, Hideo; Tachikawa, Hirokazu*; Iimoto, Takeshi*; Kawata, Yosuke*; Ogino, Haruyuki*; Okoshi, Minoru*

Journal of Radiological Protection, 38(1), p.456 - 462, 2018/03

 Percentile:100(Environmental Sciences)

Experience after the accident at the Fukushima Daiichi Nuclear Power Station has shown that there is a need to establish radiation protection criteria for radioactive waste management consistent with the criteria adopted for the remediation of existing exposure situations. A stepwise approach to setting such criteria is proposed. Initially, a reference level for annual effective dose from waste management activities in the range 1-10 mSv should be set, with the reference level being less than the reference level for ambient dose. Subsequently, the reference level for annual effective dose from waste management activities should be reduced in one or more steps to achieve a final target value of 1 mSv. The dose criteria at each stage should be determined with relevant stakeholder involvement. Illustrative case studies show how this stepwise approach might be applied in practice.

Journal Articles

The Verification tests of the melting conditions for homogenization of metallic LLW at the JAEA

Nakashio, Nobuyuki; Osugi, Takeshi; Iseda, Hirokatsu; Tohei, Toshio; Sudo, Tomoyuki; Ishikawa, Joji; Mitsuda, Motoyuki; Yokobori, Tomohiko; Kozawa, Kazushige; Momma, Toshiyuki; et al.

Journal of Nuclear Science and Technology, 53(1), p.139 - 145, 2016/01

 Times Cited Count:1 Percentile:76.09(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Radioactive waste engineering and management

Nakayama, Shinichi; Okoshi, Minoru; Shimada, Taro; Tachibana, Mitsuo; Momma, Toshiyuki; Niibori, Yuichi*; Nagasaki, Shinya*; Ahn, J.*

Genshiryoku Kyokasho "Hoshasei Haikibutsu No Kogaku", 235 Pages, 2011/01

This book is designed to provide everyone with an interest in radioactive waste issues, including students and individuals involved in engineering and public administration, with a graduate-level understanding of radioactive wastes from the scientific foundations that support radioactive waste management covering radioactive waste generation including decommissioning of nuclear facilities, treatment, disposal, clearance and their safety assessment. This book is the one volume of the English translation of the text series "An Advanced Course in Nuclear Engineering" lectured in the University of Tokyo.

JAEA Reports

Clearance of concrete generated from modification activities of JRR-3; Investigation of contamination situation of concrete

Satoyama, Tomonori; Kishimoto, Katsumi; Takaizumi, Hirohide; Hoshi, Akiko; Okoshi, Minoru; Tachibana, Mitsuo

JAEA-Technology 2009-060, 42 Pages, 2010/01

JAEA-Technology-2009-060.pdf:4.17MB

In the modification activities of JRR-3, a large volume of extremely low-level radioactive concrete debris were generated from dismantling of concrete structure around reactor body during one-piece removal of reactor body. These concrete debris are stored in the waste storage facility NL of the Nuclear Science Research Institute. The applicability of clearance to concrete debris generated from the modification activities of JRR-3 was examined as waste measures in the Nuclear Science Research Institute. First, generated place, amount of volume and radioactivity of concrete debris in the waste storage facility NL were surveyed from records in the modification of JRR-3 and data sheets of radioactive waste stored in the waste storage facility. Next, the radioactivity of samples taken from concrete debris stored in the waste storage facility NL was measured, and distribution of those radioactivity concentration was investigated to evaluate the contamination situation. In addition, activated contamination situation of concrete structure was evaluated by activated calculation. As a result, radioactivity of concrete debris was enough lower than clearance levels, so it was found that concrete debris in the waste storage facility NL was able to treat as clearance materials.

Journal Articles

Recent activities on clearance by IAEA and Japanese organizations

Okoshi, Minoru

Dekomisshoningu Giho, (31), p.32 - 44, 2005/03

The International Atomic Energy Agency (IAEA) published a Safety Guide (RS-G-1.7) on the application of the concepts of exclusion, exemption and clearance in 2004. In this Safety Guide, the IAEA proposes the activity concentrations can be applied to clearance. The Nuclear Safety Commission reevaluated their clearance levels to reflect the new technological information given in the IAEA Safety Guide and other reports. The Regulatory Authorities have been investigating and discussing regulatory rules on clearance including the verification system of clearance levels. And the Atomic Society of Japan has deliberated the technological standards for the verification of clearance levels performed by nuclear operators. In this paper the activities and outcomes by those organizations are outlined, and the issues to be solved on clearance are listed and the basic ideas for solution are discussed.

Journal Articles

Radiological characterisation of LLW arising from JAERI Tokai Research Establishment

Okoshi, Minoru; Sakai, Akihiro; Abe, Masayoshi; Tanaka, Mitsugu

IAEA-CN-87/50 (CD-ROM), p.113 - 118, 2002/12

As the result of research activities for nuclear energy utilization over 45 years, large amounts of low-level radioactive waste (LLW) are stored at Tokai Research Establishment of JAERI. In order to plan the disposal program, JAERI carried out the radiological characterization of the waste. The results show that about 34,400 tons of LLW will arise from the operation and dismantling of the facilities by the end of 2045. The total activities of beta- and gamma-radionuclides and alpha-radionuclides are about 44 PBq and 56 TBq, respectively. By using the estimated total weight and radioactivities of the waste, important radionuclides were selected from the viewpoint of safety according to the performance assessment of near surface disposal facilities. As the results, twenty-seven radionuclides including twelve alpha-ray emitting actinides were selected as the candidate important radionuclides. Those are slightly different from important radionuclides selected for commercial nuclear power plants because of materials used for facilities and so on.

Journal Articles

Clearance levels derived by European Commission

Okoshi, Minoru

Dekomisshoningu Giho, (26), p.2 - 12, 2002/11

The concept of clearance has been introduced by the International Atomic Energy Agency in 1996 and is very useful for the management of very low-level solid materials generating from the decommissioning of nuclear facilities. Therefore, the European Commission (EC) derived the specific clearance levels for metals, buildings and building rubble in RP 89 and 113, respectively. The EC also derived the general clearance levels for all solid materials generating from the regulated facilities in RP 122. Comparing the clearance levels of Japan with the unrounded levels of EC, the differences of levels are small. The biggest difference is found in Fe-55 and the EC's clearance level is about one fifth of Japanese clearance level. This is caused because the EC considers the direct ingestion of cleared building rubble by children and used the conservative ingestion rate of it. EC's discussions related to the clearance levels are very useful for Japan to derive our own clearance levels and to clear materials from regulatory control.

Journal Articles

Present status of clearance levels in Japan and other countries and related problems

Okoshi, Minoru

Hoken Butsuri, 37(3), p.197 - 207, 2002/09

The concept of clearance has been introduced by IAEA in 1996 and is very useful for the management of very low-level solid materials generating from the decommissioning of nuclear facilities. Therefore, the Nuclear Safety Commission of Japan started the derivation of clearance levels for solid materials arising from nuclear reactors in 1997 and published the reports in 1999 and 2001, respectively. EC also published the several guides to clear metals, concrete, building and other solid materials from regulatory control. Some organizations including IAEA and USNRC are still discussing how to derive the clearance levels. In this exposition, the present status of clearance in Japan and other organizations and countries is summarized. And some information to realize the concept of clearance is given, and the problems related to the clearance are also discussed.

JAEA Reports

Conceptual designs of near surface disposal facility for radioactive waste arising from the facilities using radioisotopes and research facilities for nuclear energy development and utilization

Sakai, Akihiro; Yoshimori, Michiro; Okoshi, Minoru; Yamamoto, Tadatoshi; Abe, Masayoshi

JAERI-Tech 2001-018, 88 Pages, 2001/03

JAERI-Tech-2001-018.pdf:5.66MB

no abstracts in English

Journal Articles

Derivation methods for clearance levels and safety assessments for very low-level radioactive waste disposal

Okoshi, Minoru

KURRI-KR-56, p.39 - 57, 2001/03

no abstracts in English

Journal Articles

Derivation methods on the clearance levels for nuclear reactors

Okoshi, Minoru

Hoken Butsuri, 34(4), p.353 - 358, 1999/12

no abstracts in English

Journal Articles

Deterministic approach towards establishing of clearance levels in Japan

Okoshi, Minoru; Sakai, Akihiro; Yoshimori, Michiro; Yamamoto, Hideaki; Takahashi, Tomoyuki; Kimura, Hideo

Proc. of 7th Int. Conf. on Radioactive Waste Management and Environmental Remediation (ICEM'99)(CD-ROM), 8 Pages, 1999/09

no abstracts in English

Journal Articles

Radioactive waste management; Treatment technologies from the view point of disposal

Okoshi, Minoru

Kemikaru Enjiniyaringu, 44(2), p.60 - 64, 1999/02

no abstracts in English

Journal Articles

Derivation methods of clearance levels for nuclear reactors

Okoshi, Minoru; Takahashi, Tomoyuki*; Kimura, Hideo; ; Sakai, Akihiro; Yoshimori, Michiro; Yamamoto, Hideaki

Hoken Butsuri, 34(2), p.187 - 197, 1999/00

no abstracts in English

Journal Articles

Clearance levels for solid materials arising from nuclear reactors in Japan

Nakanishi*; *; Okoshi, Minoru; Takahashi, Tomoyuki*

Proceedings of 2nd International Symposium on Release of Radioactive Material from Regulatory Control, p.55 - 63, 1999/00

no abstracts in English

Journal Articles

Integrated approach for establishing of disposal systems for highly activated waste

Sakai, Akihiro; Yoshimori, Michiro; Okoshi, Minoru; Abe, Masayoshi

Proceedings of International Waste Management Symposium '99 (Waste Manegement '99) (CD-ROM), 14 Pages, 1999/00

no abstracts in English

Journal Articles

Experience and current discussion on management of materials from decommissioning in Japan

Tanaka, Mitsugu; Okoshi, Minoru

Proceedings of Joint NEA/IAEA/EC Workshop on the Regulatory Aspects of Decommissioning, 3A, p.141 - 146, 1999/00

no abstracts in English

Journal Articles

Design concept of disposal systems for highly activated waste

Okoshi, Minoru; Abe, Masayoshi; Yoshimori, Michiro; Sakai, Akihiro

Proc. of Waste Management'98 (CD-ROM), 5 Pages, 1998/00

no abstracts in English

Journal Articles

44 (Records 1-20 displayed on this page)