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Department of Decommissioning and Waste Management
JAEA-Review 2023-001, 136 Pages, 2023/06
JAEA-Review-2023-001.pdf:10.65MB
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2021 to March 31, 2022. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM. In FY2021 radioactive wastes generated from R&D activities in NSRI were treated safely. They were about 206 m
of combustible solid wastes and 155 m of noncombustible solid wastes and 113 m of liquid wastes. After adequate treatment, 760 waste packages (in 200 L-drum equivalent) were generated. The total amounts of accumulated waste packages were 126,827 as of the end of FY2021 due to efforts of the restitution of waste packages to the Japan Radioisotope Association and volume reduction treatments of the stored waste packages. Decommissioning activities were carried out for the JAEA's Reprocessing Test Facility (JRTF), the Liquid Waste Treatment Facilities, the Compaction Facilities, and Fusion Neutronics Source (FNS) facilities. As for the R&D activities, studies on radiochemical analyses of wastes for disposal were continued. In order to pass the conformity review on the New Regulatory Requirements for waste management facilities, the Approval of the design and construction method was applied sequentially for the Nuclear Regulation Authority. The ministry of the Environment and Tokai-mura office requested JAEA to dispose of the contaminated soil generated by the accident of the Fukushima Daiichi Nuclear Power Station. The monitoring work at the playground was conducted during this period.
Nakashio, Nobuyuki*; Osugi, Takeshi; Kurosawa, Shigenobu; Ishikawa, Joji; Hemmi, Ko; Iketani, Shotaro; Yokobori, Tomohiko
JAEA-Technology 2022-016, 47 Pages, 2022/08
JAEA-Technology-2022-016.pdf:2.23MB
The Nuclear Science Research Institute (NSRI) of the Japan Atomic Energy Agency (JAEA) started operation of the Advanced Volume Reduction Facilities (AVWF) for production of waste packages for disposal of low-level radioactive solid wastes (LLW). To clarify the operating conditions for homogenization of non-metallic LLW, preliminary tests were carried out using the plasma melting furnace of the non-metal melting unit. The fluidity of molten waste influences homogenization conditions of solidified products. It was clarified that the viscosity, which is determined by the chemical composition and the melting temperature, influence the fluidity of molten waste greatly through previous literature review and the small-scale melting tests. In the preliminary tests, the simulated waste with a cold tracer loaded in 200 L drums were melted. Using the waste chemical components (basicity, iron oxide concentration) as an experimental parameter, the homogeneity of the chemical components of the solidified product was investigated and the homogenization conditions of melting tests were examined. The retention ratio of the tracer in the molten bath was also confirmed. The viscosity of the molten wastes was measured and the correlation with homogeneity was examined. In addition, the technical requirements that should be concerned in advance for future actual operation were discussed.
Department of Decommissioning and Waste Management
JAEA-Review 2022-001, 112 Pages, 2022/06
JAEA-Review-2022-001.pdf:6.51MB
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2020 to March 31, 2021. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM. In FY2020 radioactive wastes generated from R&D activities in NSRI were treated safely. They were about 267 m of combustible solid wastes and 233 m of noncombustible solid wastes and 78 m of liquid wastes. After adequate treatment, 1,448 waste packages (in 200 L-drum equivalent) were generated. The total amounts of accumulated waste packages were 130,604 as of the end of FY2020 due to efforts of the restitution of waste packages to the Japan Radioisotope Association and volume reduction treatments of the stored waste packages. Decommissioning activities were carried out for the JAEA's Reprocessing Test Facility (JRTF), the Liquid Waste Treatment Facilities, the Compaction Facilities, and Fusion Neutronics Source (FNS) facilities. As for the R&D activities, studies on radiochemical analyses of wastes for disposal were continued. In order to pass the conformity review on the New Regulatory Requirements for waste management facilities, the Approval of the design and construction method was applied sequentially for the Nuclear Regulation Authority. The ministry of the Environment and Tokai-mura office requested JAEA to dispose of the contaminated soil generated by the accident of the Fukushima Daiichi Nuclear Power Station. The monitoring work at the playground was conducted during this period.
Tsuchimochi, Akari; Suda, Shoya; Fujikura, Toshiki; Kawahara, Takahiro; Hoshi, Akiko
JAEA-Technology 2021-018, 37 Pages, 2021/10
JAEA-Technology-2021-018.pdf:2.87MB
A large amount of radioactive waste has been generated in the process of research and development in Nuclear Science Research Institute. We store the equivalent of 130,604 drums (200L) of that in our storage facilities (as of March 31, 2021) and have been developing "Radioactive Waste Information Management System" to manage them for disposal. The system started designing in FY2007 and has been in operation since FY2012. After the start of operation, it has been repaired as appropriate. In this report, we summarized the development and improvement of the system.
Department of Decommissioning and Waste Management
JAEA-Review 2021-002, 105 Pages, 2021/05
JAEA-Review-2021-002.pdf:9.68MB
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2019 to March 31, 2020. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM. In FY2019 radioactive wastes generated from R&D activities in NSRI were treated safely. They were about 323 m of noncombustible solid wastes and 111 m of liquid wastes. After adequate treatment, 2,588 waste packages (in 200 L-drum equivalent) were generated. The total amounts of accumulated waste packages were 130,223 as of the end of FY2019 due to efforts of the restitution of waste packages to the Japan Radioisotope Association and volume reduction treatments of the stored waste packages. Decommissioning activities were carried out for the JAEA's Reprocessing Test Facility (JRTF), the Liquid Waste Treatment Facilities, the Decontamination Facilities, and Fusion Neutronics Source (FNS) facilities. As for the R&D activities, studies on radiochemical analyses of wastes for disposal were continued. In order to pass the conformity review on the New Regulatory Requirements for waste management facilities, the Approval of the design and construction method was applied sequentially for the Nuclear Regulation Authority. The ministry of the Environment and Tokai-mura office requested JAEA to dispose of the contaminated soil generated by the accident of the Fukushima Daiichi Nuclear Power Plant. The monitoring work at the playground was conducted during this period.
Department of Decommissioning and Waste Management
JAEA-Review 2020-012, 103 Pages, 2020/08
JAEA-Review-2020-012.pdf:8.17MB
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2018 to March 31, 2019. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.
Department of Decommissioning and Waste Management
JAEA-Review 2019-011, 91 Pages, 2019/10
JAEA-Review-2019-011.pdf:5.25MB
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2017 to March 31, 2018. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.
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
JAEA-Review-2018-016.pdf:12.79MB
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".
Department of Decommissioning and Waste Management
JAEA-Review 2018-008, 87 Pages, 2018/07
JAEA-Review-2018-008.pdf:2.67MB
This report describes the activities of Department of Decommissioning and Waste Management (DDWM) in Nuclear Science Research Institute (NSRI) in the period from April 1, 2016 to March 31, 2017. The report covers organization and missions of DDWM, outline and operation/maintenance of facilities which belong to DDWM, treatment and management of radioactive wastes, decommissioning activities, and related research and development activities which were conducted in DDWM.
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
JAEA-Technology-2016-024.pdf:29.74MB
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.
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：10.71(Nuclear Science & Technology)no abstracts in English
Okada, Shota; Kurosawa, Ryohei; Sakai, Akihiro; Nakata, Hisakazu; Amazawa, Hiroya
JAEA-Technology 2015-016, 44 Pages, 2015/07
JAEA-Technology-2015-016.pdf:5.8MB
In this report, we calculated radioactivity concentration of radionuclides potentially contained in low level radioactive waste (LLW) generated from research, medical, and industrial facilities corresponding to dose criterion (10 
Sv/y) for near surface disposal. 220 kinds of nuclides whose half-life are more than 30 days were selected. Radioactivity concentrations corresponding to dose criterion of 40 nuclides among 220 ones were calculated by using the representative model because the concentrations of 40 nuclides had not been calculated yet. Skyshine dose from each of 19 nuclides, whose radioactivity concentration were invalid values that are larger than the specific radioactivity of nuclides, during operation of disposal facility was calculated. These radioactivity concentrations can be used as criteria of categorization of LLW between trench type and concrete vault type disposal and of preliminary selection of important nuclides of these disposals in the generic conditions.
Sakai, Akihiro; Kurosawa, Ryohei; Hara, Hironori*; Nakata, Hisakazu; Amazawa, Hiroya; Arikawa, Masanobu*; Sakamoto, Yoshiaki
JAEA-Technology 2013-039, 228 Pages, 2014/02
JAEA-Technology-2013-039.pdf:24.05MB
The sensitivity analysis of doses in terms of the environmental conditions was performed by statistical method in order to make the technical basis for the siting criteria of near surface disposal facility for low level radioactive waste generated from research, industrial and medical facilities. Doses calculated at all assumed pathways in more than 97.5% of calculation cases were able to be reduced below the target dose after control period (0.01 mSv/y) by means of equipping the disposal facility with additional engineered barriers. As a result, we concluded it was possible to safely and rationally design disposal facilities in most of the environmental parameters related to safety assessment. Another sensitivity analysis was done in order to discuss the area of disposal site. Dose at the site boundary were able to be reduce below the target dose during operation (0.05 mSv/y) whenever the distances from these facilities to the site boundary were more than 120 m, respectively.
Nakata, Hisakazu; Amazawa, Hiroya; Sakai, Akihiro; Kurosawa, Ryohei; Kanno, Naohiro*; Kashima, Takahiro*; Sakamoto, Yoshiaki
JAEA-Technology 2013-036, 47 Pages, 2014/02
JAEA-Technology-2013-036.pdf:5.27MB
The Low-level Radioactive Waste Disposal Project Center will construct near surface disposal facilities. The disposal facilities consist of concrete pit type for low-level radioactive wastes and trench type for very low level radioactive wastes. As for the trench type disposal facility, two kinds of facility designs are on projects -one for normal trench type disposal facilities and the other for trench type disposal facilities with geomembrane liners that could prevent from causing environmental effects of non radioactive toxic materials. This study examined mechanical strength and permeability properties to assess the durability on the basis of an indoor accelerated exposure experiment targeting the liner materials presumed to avail the conceptual design so far. Its results will be used for the basic and detailed design henceforth by confirming the empirical degradation characteristic with the progress of the exposure time.
Yoshioka, Tatsuji; Kanzaki, Noriko; Osawa, Hideaki; Hayakawa, Tsuyoshi; Nakata, Hisakazu
JAEA-Review 2013-045, 158 Pages, 2014/01
JAEA-Review-2013-045.pdf:37.31MB
Local partnership approach to achieve stakeholder consensus on low-level waste disposal, with particular focus on the siting of repositories are adopted in Europe. Especially in Belgium and Slovenia, final repository site had been decided in each country. The authors investigate on these two cases on the basis of interviews with implementing organizations for final disposal, representatives of local partnerships and citizens concerned so that the problem of introducing a local partnership in Japan can be examined. Its results are used as a reference for studying measures to determine the radioactive final repository site in Japan.
Sudo, Tomoyuki; Mimura, Ryuji; Ishihara, Keisuke; Satomi, Shinichi; Myodo, Masato; Momma, Toshiyuki; Kozawa, Kazushige
JAEA-Technology 2011-015, 24 Pages, 2011/06
JAEA-Technology-2011-015.pdf:2.28MB
The super compactor in the Advanced Volume Reduction Facilities (AVRF) treats metal wastes mainly generated from research reactors in the Nuclear Science Research Institute of JAEA. Those wastes are compacted from one third to one fourth with maximum 2,000-ton force. In the trial operation using simulated wastes, some technical problems were found to be improve for the stable operation. One problem is the motion mechanism for carrying wastes before and after compaction. The other problem is the mechanism for treating the irregular supercompacted products. In this report, we describe the detail and the result of improvement on those problems for the stable operation in the super compactor.
Amazawa, Hiroya; Sakai, Akihiro; Sakamoto, Yoshiaki; Nakata, Hisakazu; Yamamoto, Masayuki*; Kawata, Yosuke*; Kihara, Shinji
JAEA-Technology 2010-043, 153 Pages, 2011/01
JAEA-Technology-2010-043.pdf:9.72MB
The Low-Level Radioactive Waste Disposal Project Center of Japan Atomic Energy Agency will establish a sitting criterion and procedure in a fair and transparent manner to settle on a near surface disposal facility for low level radioactive wastes generated from research, industrial and medical facilities, based on "Plan Concerning the Disposal Business Execution". Therefore, reasonable conceptual design of the disposal facilities will be planned under premise conditions of sitting condition on natural and social environment, waste form condition including radioactive inventory and waste packages, and technical standards based on "Law for the Regulations of Nuclear Source Material, Nuclear Fuel Material and Reactors" and "Law concerning Prevention of Radiation Hazards due to Radioisotopes, etc." and so on. This report summarizes the results of the investigation on the sitting condition in these premise conditions for conceptual designs of the disposal facilities.
Sudo, Tomoyuki; Nakashio, Nobuyuki; Osugi, Takeshi; Mimura, Ryuji; Ishihara, Keisuke; Satomi, Shinichi; Myodo, Masato; Momma, Toshiyuki; Kozawa, Kazushige
JAEA-Technology 2010-041, 38 Pages, 2011/01
JAEA-Technology-2010-041.pdf:4.73MB
The super compactor in the AVRF treats compactible metal wastes mainly generated from research reactors in the Nuclear Science Research Institute of JAEA. Those wastes are compacted with the maximum about 2,000-ton force. The supercompacted wastes are packed into the container and then immobilized with cementitious materials. The solidified wastes (containing supercompacted wastes) become an object for near surface disposal with artificial barrier. For disposal, the solidified wastes must be satisfied the technical criteria. One of the important indicators is the void ratio in the solidified wastes. In this report, we manufactured the supercompacted wastes with the ordinary treatment method for actual wastes treated in the AVRF and immobilized with a mortar grout. The void ratio of the solidified wastes were evaluated in consideration for concrete vault disposal. As a result, We confirmed the integrity of the solidified wastes from a point of view of void ratio.
Tohei, Toshio; Nakashio, Nobuyuki; Osugi, Takeshi; Ishikawa, Joji; Mizoguchi, Takafumi; Hanawa, Ritsu; Someya, Keita*; Takahashi, Kenji*; Iseda, Hirokatsu; Kozawa, Kazushige; et al.
JAEA-Technology 2010-008, 28 Pages, 2010/06
JAEA-Technology-2010-008.pdf:5.0MB
The Waste Volume Reduction Facility (WVRF) was constructed for volume reduction and the chemical stabilization of the low level radioactive waste in the Nuclear Science Research Institute of JAEA. The metal melting system in the WVRF treats radioactive metal waste. From the experience of trial operations, the improvement has conducted on the casting process in the metal melting system. The performance of the improved casting process was verified through the trial operations from Oct. 2008. In this report, we describe the reduction of the processing time, of the utilities consumption, of the load of maintenance on the improved casting process.
Tohei, Toshio; Someya, Keita; Takahashi, Kenji; Iseda, Hirokatsu; Kozawa, Kazushige; Momma, Toshiyuki
JAEA-Technology 2009-031, 29 Pages, 2009/06
JAEA-Technology-2009-031.pdf:21.66MB
The Waste Volume Reduction Facility (WVRF) was constructed for volume reduction and the chemical stabilization of the low level radioactive waste (LLW). The metal melting system in the WVRF treats radioactive metal waste. This system has been conducted commissioning since the FY 2003. It was found, from the experience of commissioning, that the improvement of casting process in the metal melting system can be reduced the processing cost, maintenance load, and dose to workers. We planed modification of the device, and embodied from FY 2006 to FY 2007. As a result, we properly improved the casting process. In this report, we describe the idea for improvement of the casting process, the detail of improvement and the estimate of improvement.
