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Yonomoto, Taisuke; Nakashima, Hiroshi*; Sono, Hiroki; Kishimoto, Katsumi; Izawa, Kazuhiko; Kinase, Masami; Osa, Akihiko; Ogawa, Kazuhiko; Horiguchi, Hironori; Inoi, Hiroyuki; et al.
JAEA-Review 2020-056, 51 Pages, 2021/03
A group named as "The group for investigation of reasonable safety assurance based on graded approach", which consists of about 10 staffs from Sector of Nuclear Science Research, Safety and Nuclear Security Administration Department, departments for management of nuclear facility, Sector of Nuclear Safety Research and Emergency Preparedness, aims to realize effective graded approach (GA) about management of facilities and regulatory compliance of JAEA. The group started its activities in September, 2019 and has had discussions through 10 meetings and email communications. In the meetings, basic ideas of GA, status of compliance with new regulatory standards at each facility, new inspection system, etc were discussed, while individual investigation at each facility were shared among the members. This report is compiled with expectation that it will help promote rational and effective safety management based on GA by sharing contents of the activity widely inside and outside JAEA.
Iketani, Shotaro; Yokobori, Tomohiko; Ishikawa, Joji; Yasuhara, Toshiyuki*; Kozawa, Toshiyuki*; Takaizumi, Hirohide*; Momma, Takeshi*; Kurosawa, Shingo*; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.
JAEA-Review 2018-016, 46 Pages, 2018/12
Japan Atomic Energy Agency (JAEA) adopts melting process for the waste processing and packaging method of radioactive miscellaneous solid waste in NSRI because melting process is effective in radioactivity evaluation, volume reduction, and stabilization treatment. Metal melting processing facilities, Incinerator, and Nonmetal melting processing facilities (hereinafter referred to as melting process facilities) have taken lots of safety measures, including measures for preventing the recurrence of the fire accidents. To exchange opinions and discuss the validity of these measures and so on with internal personnel and external experts, "Discussions on Melting Process Facilities" was held. As a document collection, this paper summarizes presentation materials of discussion meetings. Presentation materials describe "Outline of AVRF", "Safety measures in the melting facilities in WVRF", "Operation management of the melting facilities in WVRF", "Comparison of the past accident cases between facilities in and outside Japan and WVRF", and "Introduction of past accident cases and safety measures in other facilities from each committee".
Ogoshi, Yurie; Satoyama, Tomonori; Kishimoto, Katsumi; Nanri, Tomohiro; Suzuki, Takeshi; Tomioka, Osamu; Takaizumi, Hirohide*; Kanno, Tomoyuki*; Maruyama, Tatsuya*
JAEA-Technology 2017-017, 152 Pages, 2017/08
At Nuclear Science Research Institute, clearance works for about 4,000 tons of extremely low-level radioactive concrete debris, which were generated from the modification activities of JRR-3 from FY 1985 to FY 1989 and stored in the waste storage facility NL, carried out. First of this clearance works, method for measuring and evaluating radioactivity concentration was approved by Minister of MEXT on July 25, 2008. And then, clearance works were started from FY 2009. Measuring and evaluating radioactivity concentration was achieved by using the approved method, and was confirmed by government. And then, clearance works were completed in FY 2014. The clearance concrete was recycled as a material for restoration works of the 2011 off the Pacific coast of Tohoku Earthquake. This report summarizes the results of measuring and evaluating radioactivity concentration, achievement of confirmation by government, recycling of cleared concrete and cost for clearance works.
Ishihara, Keisuke; Yokota, Akira; Kanazawa, Shingo; Iketani, Shotaro; Sudo, Tomoyuki; Myodo, Masato; Irie, Hirobumi; Kato, Mitsugu; Iseda, Hirokatsu; Kishimoto, Katsumi; et al.
JAEA-Technology 2016-024, 108 Pages, 2016/12
Radioactive isotope, nuclear fuel material and radiation generators are utilized in research institutes, universities, hospitals, private enterprises, etc. As a result, various low-level radioactive wastes (hereinafter referred to as non-nuclear radioactive wastes) are produced. Disposal site for non-nuclear radioactive wastes have not been settled yet and those wastes are stored in storage facilities of each operator for a long period. The Advanced Volume Reduction Facilities (AVRF) are built to produce waste packages so that they satisfy requirements for shallow underground disposal. In the AVRF, low-level beta-gamma solid radioactive wastes produced in the Nuclear Science Research Institute are mainly treated. To produce waste packages meeting requirements for disposal safely and efficiently, it is necessary to cut large radioactive wastes into pieces of suitable size and segregate those depending on their types of material. This report summarizes activities of pretreatment to dispose of non-nuclear radioactive wastes in the AVRF.
Satoyama, Tomonori; Nanri, Tomohiro; Kishimoto, Katsumi
Hoken Butsuri, 49(4), p.180 - 189, 2014/12
JAEA planned to apply the clearance system to slightly contaminated concrete debris with radionuclides, which was generated from the modification of the JRR-3. The modification work was conducted from 1985 to 1990 and the generated concrete debris has been stored as radioactive waste in interim storage facilities. JAEA established procedures for measuring and evaluating the radioactivity concentration of sored concrete debris. In 2008, the authority approved these procedures for clearance. Since 2009, JAEA have been measuring and evaluating the radioactivity concentration of concrete debris, using the approved procedures. By the end of 2012, the authority had confirmed the correctness of our measurement and evaluation results on about 2,600 tons of concrete debris. About 1,800 tons of those cleared concrete were recycled to flat surface subsidence in the NSRI caused by the Great East Japan Earthquake, and also used as base material to construct new buildings and parking lots.
Tachibana, Mitsuo; Kishimoto, Katsumi; Shiraishi, Kunio
International Nuclear Safety Journal (Internet), 3(4), p.16 - 24, 2014/11
Three research reactors were permanently shut down in the Nuclear Science Research Institute (NSRI) of the Japan Atomic Energy Agency (JAEA) as of October 2014. Safe storage or one-piece removal method was applied to decommissioning of these research reactors depending on decommissioning cost and utilization of facilities and so on. Various kinds of data and experiences were obtained through decommissioning of these research reactors. This report shows data and experiences on the research reactors decommissioning in the NSRI of the JAEA.
Satoyama, Tomonori; Nanri, Tomohiro; Kishimoto, Katsumi
Dekomisshoningu Giho, (49), p.11 - 21, 2014/03
Japan Atomic Energy Agency at the Nuclear Science Research Institute (NSRI) planned to apply the clearance system to about 4,000 tons of slightly contaminated concrete debris with radionuclides, which was generated from the modification of the Japan Research Reactor No.3 (JRR-3). The modification work was conducted from 1985 to 1990 and the generated concrete debris has been stored as radioactive waste in interim storage facilities in the NSRI. In 2008, the authority approved procedures for measuring and evaluating the radioactivity concentration of stored concrete debris. Since 2009, NSRI have been measuring and evaluating the radioactivity concentration of concrete debris, using the approved procedures. By the end of 2013, the authority had confirmed the correctness of our measurement and evaluation results on about 3,000 tons of concrete debris. About 1,800 tons of those cleared concrete were recycled as backfilling material in depressed areas around buildings caused by the Great East Japan Earthquake, and as roadbed material of the parking lots in the NSRI.
Satoyama, Tomonori; Kishimoto, Katsumi; Hoshi, Akiko; Takaizumi, Hirohide; Tsutsumi, Masahiro; Inanobe, Hiroshi; Yoshimori, Michiro
JAEA-Technology 2011-003, 53 Pages, 2011/03
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.
Satoyama, Tomonori; Kishimoto, Katsumi; Takaizumi, Hirohide; Hoshi, Akiko; Okoshi, Minoru; Tachibana, Mitsuo
JAEA-Technology 2009-060, 42 Pages, 2010/01
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.
Kikuchi, Mitsuru; Tamai, Hiroshi; Matsukawa, Makoto; Fujita, Takaaki; Takase, Yuichi*; Sakurai, Shinji; Kizu, Kaname; Tsuchiya, Katsuhiko; Kurita, Genichi; Morioka, Atsuhiko; et al.
Nuclear Fusion, 46(3), p.S29 - S38, 2006/03
Times Cited Count:13 Percentile:41.02(Physics, Fluids & Plasmas)The National Centralized Tokamak (NCT) facility program is a domestic research program for advanced tokamak research to succeed JT-60U incorporating Japanese university accomplishments. The mission of NCT is to establish high beta steady-state operation for DEMO and to contribute to ITER. The machine flexibility and mobility is pursued in aspect ratio and shape controllability, feedback control of resistive wall modes, wide current and pressure profile control capability for the demonstration of the high-b steady state.
Suzuki, Takeshi; Nakano, Masahiro; Okawa, Hiroshi; Terunuma, Akihiro; Kishimoto, Katsumi; Yano, Masaaki
JAERI-Tech 2005-018, 84 Pages, 2005/03
no abstracts in English
Kishimoto, Katsumi; Arigane, Kenji*
JAERI-Tech 2005-016, 83 Pages, 2005/03
Revaluation to activation activity of reactor evaluated at the notification of dismantling submitted in 1997 was carried out in JRR-2 where decommissioning was advanced now. In the revaluation, estimation accuracy on neutron streaming at various horizontal experimental tubes was improved by applying 3 dimensional model to neutron transport calculation that had been carried out by 2 dimensional model, and calculating with TORT. As the result, excessive overestimations on horizontal experimental tubes and biological shield that had greatly contributed to total activation activity in evaluation at the notification of dismantling was revised, sum of their activation activities in the revaluation decreased to 1/18(case after 1 year from the permanent shutdown of reactor) of evaluation at the notification of dismantling, and the structural materials that had large activation activity were changed. By the above, it was shown that introducing 3 dimensional model was effective in evaluation on activation activity of the research reactor that had a lot of various experimental tubes.
Nakano, Masahiro; Okawa, Hiroshi; Suzuki, Takeshi; Kishimoto, Katsumi; Terunuma, Akihiro; Yano, Masaaki
Dekomisshoningu Giho, (30), p.11 - 24, 2004/09
Japan Research Reactor No.2(JRR-2), heavy water moderated and cooled tank type research reactor with maximum thermal power of 10MW,was operated for over 36 years, and was permanently shut down in December, 1996. In 1997, decommissioning plan was submitted to the STA, and dismantling was begun. Decommissioning program of JRR-2 is divided into 4 phases. Phase 1, 2 had already been completely finished without any trouble. Furthermore, the phase 3 was also finished in February, 2004 as planned. On exposure of worker in phase 1, 2 and 3, it was achieved to control lower than the estimate. On exposure of worker in phase 1, 2 and 3, it was achieved to control lower than the estimate. Reactor will be removed in phase 4 by one piece removal technique. The reactor building is planned to use effectively as a hot experimental facilities after decommissioning. The decommissioning plan was changed that the reactor would be kept in safety storage.
Akutsu, Atsushi; Kishimoto, Katsumi; Sukegawa, Takenori; Shimada, Taro
JAERI-Tech 2003-090, 75 Pages, 2004/01
The Japan Research Reactor No.1 (JRR-1) that was constructed first in Japan was permanently shut down after operation from 1957 to 1968. At present, the reactor part is in safe store conditions. The JRR-1 facility is being used as an exhibition room for the time being, and will be dismantled in the future. In consideration of future dismantling of the facility, the radioactive inventory in reactor part was calculated using computer codes that are Two-Dimensional Discrete Ordinates Transport Code (DORT) and Oak Ridge Isotope Generation and Depletion Code (ORIGEN-MD). The average concentration of radioactivity is estimated to be 6.40 Bq/g in the core tank as of April, 2002. It is also expected that the low level waste (LLW) weights approximately 400kg and very low level waste (VLLW) weights approximately 14,000kg, and the waste which doesn't need to deal as a radioactive material weights approximately 250,000kg.
Nakano, Masahiro; Arigane, Kenji; Okawa, Hiroshi; Suzuki, Takeshi; Kishimoto, Katsumi; Terunuma, Akihiro; Yano, Masaaki; Sakuraba, Naotoshi; Oba, Nagamitsu
JAERI-Tech 2003-072, 92 Pages, 2003/08
The decommissioning plan of the Japan Research reactor No2(JRR-2), decommissioning activities until the first half of phase-3, radioactive wastes and exposure dose of workers are described in this report. Since the first criticality in October 1960, JRR-2 had been operated about 36 years for various experiments. However, JRR-2 was permanent shutdown in December 1996 based on JAERI's long term plan, and the decommissioning of the JRR-2 was started in August 1997. Decommissioning of the JRR-2 was planed for 11 years from 1997 to 2007 and the program was divided into 4 phases. The decommissioning activities of the phase-1, phase-2 and the first half of phase-3 had already completed as planned in March 1998, February 2000, March 2002, respectively. The decommissioning activities of the later half of Phase-3 (dismantling of the reactor cooling systems) are carrying out at present time with planed 2002 and 2003 fiscal years.
Iwashita, Mitsushige*; Arigane, Kenji; Kishimoto, Katsumi; Seiki, Y.*; Fukumura, Nobuo*; Mio, K.*
Journal of Nuclear Science and Technology, 37(Suppl.1), p.372 - 378, 2000/03
no abstracts in English
Kishimoto, Katsumi; Bamba, Masao; Arigane, Kenji
JAERI-Conf 99-006, p.96 - 101, 1999/08
no abstracts in English
Kishimoto, Katsumi; Bamba, Masao; Arigane, Kenji
Proc. of 1999 Workshop on the Utilization of Research Reactors, p.96 - 101, 1999/00
no abstracts in English
Kishimoto, Katsumi; Funasaka, Hideyuki; Shiraishi, Kunio; Yanagihara, Satoshi*; Matsuhashi, Kazuya*
no journal, ,
In the Fukushima Daiichi Nuclear Power Plant, normal decommissioning scenarios can't be applied because the facility characteristics are different from the other. Therefore, we have studied on influence for scenarios by the characteristics.
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.