Clearance of concrete generated from modification activities of JRR-3; Method for measuring and evaluating of radioactivity concentration

Satoyama, Tomonori; Kishimoto, Katsumi; Hoshi, Akiko; Takaizumi, Hirohide; Tsutsumi, Masahiro; Inanobe, Hiroshi; Yoshimori, Michiro

JAEA-Technology 2011-003, 53 Pages, 2011/03

JAEA-Technology-2011-003.pdf:1.6MB

In Nuclear Science Research Institute, clearance activities for extremely low-level radioactive concrete debris, which were generated from the modification activities of JRR-3 from FY 1985 to FY 1989 and now are stored in the waste storage facility NL, have been carried out in order to plan reasonable disposal and effectively reusing of concrete waste, moreover to secure storage capacity at the waste storage facilities. Method for measuring and evaluating of radioactivity concentration was applied for approval of Minister of MEXT on November 8, 2007, approved on July 25, 2008. After that the necessary equipments for clearance works were equipped and operational safety progress and manuals for clearance works were prepared. So clearance works were started in FY 2009. This report summarizes the method for measuring and evaluating of radioactivity concentration for concrete generated from modification activities of JRR-3.

Selection of important nuclides from the viewpoint of safety assessment for disposal of radioactive waste arising from research institutes, 2; Analytical scheme for nuclide composition in radwastes arising from research and testing reactor and post-irradiation examination facilities

Asai, Shiho; Sakai, Akihiro; Yoshimori, Michiro; Kihara, Shinji

JAERI-Tech 2003-071, 46 Pages, 2003/08

JAERI-Tech-2003-071.pdf:4.31MB

As part of survey concerning radioactive inventory of radwastes arising from research institutes, an analytical scheme has been studied for verifying their nuclide composition based on calculation analysis and record, in consideration of the its characteristics. In this study, radwastes are used as samples, which arise from research and testing reactors and post-irradiation examination facilities (PIE facilities). Though separation procedures are simplified and rationalized, quantifiable values could be obtained with relative errors under 10% for almost all the samples containing nuclides like Ni and U which concentrations are low, and recoveries were high on the whole. These show that the analytical scheme is useful for chemical separation of radwastes arising from research and testing reactors and PIE facilities.

Selection of important nuclides from the viewpoint of safety assessment for disposal of radioactive waste arising from research institute, 1; Evaluation of nuclide composition rates in waste generated from main research facilities

Sakai, Akihiro; Yoshimori, Michiro; Abe, Masayoshi

JAERI-Tech 2000-012, p.107 - 0, 2000/03

JAERI-Tech-2000-012.pdf:6.47MB

no abstracts in English

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

https://doi.org/10.5453/jhps.34.187

no abstracts in English

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

Safety demonstration test for the disposal of very low level concrete waste

Abe, Masayoshi; Okoshi, Minoru; Yoshimori, Michiro

Dekomisshoningu Giho, 0(15), p.50 - 58, 1996/12

http://www.randec.or.jp/publish/documents/gihou/Decommissioning%20gihou_15.pdf

no abstracts in English

Near surface disposal of VLLW from reactor decommissioning and safety requirements

Okoshi, Minoru; Yoshimori, Michiro

Proc. of 3rd Japan-Russia Joint Symp. on Radiation Safety, 0, p.75 - 85, 1995/00

no abstracts in English

Clearance of concrete debris generated from modification work of JRR-3, 5; Result of measurement and evaluation of radioactivity distribution

Nanri, Tomohiro; Kishimoto, Katsumi; Satoyama, Tomonori; Takaizumi, Hirohide; Kanno, Tomoyuki; Maruyama, Tatsuya; Yoshimori, Michiro

no journal, , 

no abstracts in English

Effective utilization of concrete debris generated from nuclear reactors; Clearance of concrete debris generated from modification work of JRR-3

Kishimoto, Katsumi; Satoyama, Tomonori; Takaizumi, Hirohide; Kanno, Tomoyuki; Maruyama, Tatsuya; Yoshimori, Michiro

no journal, , 

We have been storing about 4000 tons of very low-level radioactive concrete debris as radioactive wastes generated from the modification of JRR-3 between 1985 and 1990. At that time, the clearance system was not a part of our regulatory law. We conducted a preliminary survey of contamination levels, and then established procedures for measuring and evaluating the radioactivity concentration. In 2008, the government authorized our procedures for clearance. Since FY 2009, we have measured the radioactivity concentration of concrete debris, using the government-authorized procedures. By the end of FY 2012, the government had confirmed the correctness of our measurements and evaluation results on about 1900 tons of concrete debris. We processed the concrete debris that was approved by the government for recycling. By the end of FY 2012, we had reused about 600 tons of concrete debris as backfilling material in depressed areas around buildings in the Nuclear Science Research Institute.

Clearance activities of concrete generated from modification of JRR-3, 1; Over view

Yoshimori, Michiro; Satoyama, Tomonori; Oki, Keiichi; Naito, Akira; Okoshi, Minoru; Hoshi, Akiko

no journal, , 

no abstracts in English