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Journal Articles

Prototype fast breeder reactor "Monju" start of unloading operation of the fuel assembly from the core

Koga, Kazuhiro*; Suzuki, Kazunori*; Takagi, Tsuyohiko; Hamano, Tomoharu

FAPIG, (196), p.8 - 15, 2020/02

The prototype fast breeder reactor Monju has already started (from June 2017) the unloading operation period (about 5.5 years: until the end of 2022) of the fuel assembly, which is the first stage of decommission. Among them, the first "Processing of fuel assembly" operation (86 in total) was conducted from August 2018 to January 2019 as the first handling of the fuel assembly. Fuji Electric provided technical support, such as dispatching technicians throughout the period, in cooperation with Japan Atomic Energy Agency for the "Processing of fuel assembly" operation, and contributed to the completion of the operation while experiencing various troubles. This manuscript introduces the contents of the first "Processing of fuel assembly" operation and the overview of the trouble status. This manuscript is a sequel to FAPIG No.194 "Prototype Fast Breeder Reactor Monju Decommissioning and Unloading Operation of the Fuel Assembly from the Core", please refer to it.

Journal Articles

The Surface composition of asteroid 162173 Ryugu from Hayabusa2 near-infrared spectroscopy

Kitazato, Kohei*; Milliken, R. E.*; Iwata, Takahiro*; Abe, Masanao*; Otake, Makiko*; Matsuura, Shuji*; Arai, Takehiko*; Nakauchi, Yusuke*; Nakamura, Tomoki*; Matsuoka, Moe*; et al.

Science, 364(6437), p.272 - 275, 2019/04

 Times Cited Count:79 Percentile:0.09(Multidisciplinary Sciences)

The near-Earth asteroid 162173 Ryugu, the target of Hayabusa2 sample return mission, is believed to be a primitive carbonaceous object. The Near Infrared Spectrometer (NIRS3) on Hayabusa2 acquired reflectance spectra of Ryugu's surface to provide direct measurements of the surface composition and geological context for the returned samples. A weak, narrow absorption feature centered at 2.72 micron was detected across the entire observed surface, indicating that hydroxyl (OH)-bearing minerals are ubiquitous there. The intensity of the OH feature and low albedo are similar to thermally- and/or shock-metamorphosed carbonaceous chondrite meteorites. There are few variations in the OH-band position, consistent with Ryugu being a compositionally homogeneous rubble-pile object generated from impact fragments of an undifferentiated aqueously altered parent body.

Journal Articles

Prototype fast breeder reactor "Monju" decommissioning and unloading operation of the fuel assembly from the core

Koga, Kazuhiro*; Suzuki, Kazunori*; Hamano, Tomoharu; Takagi, Tsuyohiko

FAPIG, (194), p.6 - 11, 2018/02

The prototype fast breeder reactor "Monju" was decided to decommission by Japanese government on 21 December 2016. After that, Japan Atomic Energy Agency (JAEA) submitted "Monju decommissioning basic plan" to MEXT (Charge ministry) on 13 June 2017, then the unloading operation period (about 5.5 years) of the fuel assembly, which is the first stage of decommission, has started. Fuji Electric is proceeding with various preparations in cooperation with JAEA for the safe work of the unloading operation. This manuscript introduces the outline of preparation situation such as maintenance and inspection for the unloading operation.

Journal Articles

Development of a robot simulation system for remotely operated robots for operator proficiency training and robot performance verification

Kawabata, Kuniaki; Suzuki, Kenta; Isowa, Mitsuru*; Horiuchi, Kazunori; Ito, Rintaro

Proceedings of 14th International Conference on Ubiquitous Robots and Ambient Intelligence (URAI 2017) (USB Flash Drive), p.561 - 564, 2017/06

This paper describes the current status of the development of a simulation system for remotely operated robots. The system will be used for operator proficiency training and robot performance verification. Our purpose for developing this system is to contribute to decommissioning of the Fukushima Daiichi Nuclear Power Station (FDNPS). The simulator system was designed using Choreonoid, a simulator development tool. The effects of view disturbances, communication failures, and so on are extended functions that are implemented on the simulator. The effects of water submergence on the physical behavior of underwater robots are also implemented. In this paper, we introduce the prototype of the robotic simulator system with the newly implemented extended functions. Some examples of system output are shown.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2014

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Kikuchi, Masaaki*; Sakauchi, Nobuyuki*; et al.

JAEA-Review 2015-030, 115 Pages, 2015/12

JAEA-Review-2015-030.pdf:25.28MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2014. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2013

Watanabe, Hitoshi; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki*; Otani, Kazunori*; Hiyama, Yoshinori*; Goto, Ichiro*; Kibe, Satoshi*; et al.

JAEA-Review 2014-040, 115 Pages, 2015/01

JAEA-Review-2014-040.pdf:4.26MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), the effluent control of liquid waste discharged from the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency has been performed. This report describes the effluent control results of the liquid waste in the fiscal year 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other nuclear fuel material usage facilities were much lower than the limits authorized by the above regulations.

JAEA Reports

Report of "The 2013 International Forum on Peaceful Use of Nuclear Energy, Nuclear Non-proliferation and Nuclear Security; Ensuring Nuclear Non-proliferation and Nuclear Security of Nuclear Fuel Cycle Options in consideration of the Accident at TEPCO's Fukushima Daiichi Nuclear Power Station"

Yamamura, Tsukasa; Suda, Kazunori; Tomikawa, Hirofumi; Suzuki, Mitsutoshi; Kuno, Yusuke; Mochiji, Toshiro

JAEA-Review 2014-011, 74 Pages, 2014/03

JAEA-Review-2014-011.pdf:6.18MB

The Japan Atomic Energy Agency held "International Forum on Peaceful Use of Nuclear Energy, Nuclear Non-proliferation and Nuclear Security; Ensuring Nuclear Non-Proliferation and Nuclear Security of Nuclear Fuel Cycle Options in consideration of the Accident at TEPCO's Fukushima Daiichi Nuclear Power Station" on 3 and 4 December 2013. Keynote speakers from Japan, the United States, France and International Atomic Energy Agency (IAEA), respectively explained their efforts. In two panel discussions, entitled "Nuclear non-proliferation and nuclear security measures of nuclear fuel cycle options in consideration of the Accident at TEPCO's Fukushima Daiichi Nuclear Power Station" and "Roles of safeguards and technical measures for ensuring nuclear non-proliferation for nuclear fuel cycle options", active discussions were made. This report includes abstracts of keynote speeches, summaries of two panel discussions and materials of the presentations in the forum.

JAEA Reports

Annual report on the effluent control of low level liquid waste in Nuclear Fuel Cycle Engineering Laboratories FY2012

Sumiya, Shuichi; Watanabe, Hitoshi; Miyagawa, Naoto; Nakano, Masanao; Fujita, Hiroki; Kono, Takahiko; Inoue, Kazumi; Yoshii, Hideki; Otani, Kazunori*; Hiyama, Yoshinori*; et al.

JAEA-Review 2013-041, 115 Pages, 2014/01

JAEA-Review-2013-041.pdf:19.01MB

Based on the regulations (the safety regulation of Tokai reprocessing plant, the safety regulation of nuclear fuel material usage facilities, the radiation safety rule, the regulation about prevention from radiation hazards due to radioisotopes, which are related with the nuclear regulatory acts, and the local agreement concerning with safety and environment conservation around nuclear facilities, the water pollution control law, and bylaw of Ibaraki prefecture), this report describes the effluent control results of liquid waste discharged from the JAEA's Nuclear Fuel Cycle Engineering Laboratories in the fiscal year 2012, from 1st April 2012 to 31st March 2013. In this period, the concentrations and the quantities of the radioactivity in liquid waste discharged from the reprocessing plant, the plutonium fuel fabrication facilities, and the other facilities were much lower than the authorized limits of the above regulations.

JAEA Reports

Review of the International Forum on Peaceful Use of Nuclear Energy and Nuclear Security; Taking the lessons learned from Fukushima Daiichi Nuclear Power Plant Accident to the 2012 Seoul Nuclear Security Summit

Tazaki, Makiko; Suda, Kazunori; Suzuki, Mitsutoshi; Kuno, Yusuke; Mochiji, Toshiro

JAEA-Review 2012-021, 83 Pages, 2012/06

JAEA-Review-2012-021.pdf:8.17MB

The Japan Atomic Energy Agency (JAEA) held "2011 International Forum on the Peaceful Use of Nuclear Energy and Nuclear Security; Taking the lessons learned from Fukushima Daiichi Nuclear Power Plant accident to the 2012 Seoul Nuclear Security Summit" on 8 and 9 December, 2011. It intended to articulate effective strategies and measures for strengthening nuclear security using lessons learned from the Fukushima nuclear accident. Moreover, it was expected to explore comprehensive approaches which could contribute to enhancing both nuclear safety and security in order to support sustainable and appropriate development of the peaceful use of nuclear energy. This report includes abstracts of keynote speeches, summary of panel discussions and materials of the presentations in the forum.

Journal Articles

JAEA's actions and contributions to the strengthening of nuclear non-proliferation

Suda, Kazunori; Suzuki, Mitsutoshi; Mochiji, Toshiro

AIP Conference Proceedings 1448, p.16 - 21, 2012/06

 Times Cited Count:0 Percentile:100

Japan, a non-nuclear weapons state, has established a commercial nuclear fuel cycle including LWRs, and now is developing a fast neutron reactor fuel cycle as part of the next generation nuclear energy system, with commercial operation targeted for 2050. Japan Atomic Energy Agency (JAEA) is the independent administrative agency for conducting comprehensive nuclear R&D in Japan after the merger of Japan Atomic Energy Research Institute (JAERI) and Japan Nuclear Cycle Development Institute (JNC). JAEA and its predecessors have extensive experience in R&D, facility operations, and safeguards development and implementation for new types of nuclear facilities for the peaceful use of nuclear energy. As the operator of various nuclear fuel cycle facilities and numerous nuclear materials, JAEA makes international contributions to strengthen nuclear non-proliferation. This paper provides an overview of JAEA's development of nuclear non-proliferation and safeguards technologies, including remote monitoring of nuclear facilities, environmental sample analysis methods and new efforts since the 2010 Nuclear Security Summit in Washington D.C.

Journal Articles

Improvements in plastic enclosure system for glovebox decommissioning

Watahiki, Masatoshi; Akai, Masanori; Nakai, Koji; Iemura, Keisuke; Yoshino, Masanori*; Hirano, Hiroshi*; Kitamura, Akihiro; Suzuki, Kazunori

Nippon Genshiryoku Gakkai Wabun Rombunshi, 11(1), p.101 - 109, 2012/02

Gloveboxes used for plutonium fuel development and fabrication are eventually dismantled for replacement or decommissioning. Since equipment interior and the inner surface of gloveboxes are contaminated in radioactive materials, glovebox dismantling work is performed by workers wearing an air fed suit with mechanical tools in a plastic enclosure system to control the spread of contamination. Various improvements of enclosure system are implemented including modification of the rooms to decontaminate and undress the air fed suit and introduction of inflammable filter and safety film near the size reduction workspace against fire. We describe the countermeasures deployed in the enclosure system against potential hazards and how these devices work in the real dismantling activities.

Journal Articles

Decommissioning plutonium fuel fabrication facility

Iemura, Keisuke; Nakai, Koji; Watahiki, Masatoshi; Kitamura, Akihiro; Suzuki, Kazunori; Aoki, Yoshikazu

Dekomisshoningu Giho, (43), p.2 - 9, 2011/03

Plutonium fuel fabrication facility is constructed in 1972 and it is almost 40 years of age and equipment and components comprises the facility start degrading. Therefore we need to start dismantling gloveboxes from old ones first and at the same time to maintain the facility components and structures and gloveboxes as necessary. Also, since waste storage space is limited in the site, we effectively use open spaces generated after removing gloveboxes and equipment as temporal waste storage space. After shipping these wastes from the facility, final characterization of the facility will be conducted and demolition of the facility will be take place.

Journal Articles

A Consideration on proliferation resistance of a FBR fuel cycle system

Inoue, Naoko; Kaji, Naoya; Suda, Kazunori; Kawakubo, Yoko; Suzuki, Mitsutoshi; Koyama, Tomozo; Kuno, Yusuke; Senzaki, Masao

Proceedings of INMM 51st Annual Meeting (CD-ROM), 10 Pages, 2010/07

JAEA Reports

Development of image-analysis method of plutonium samples by imaging plate; Measurement of plutonium samples in mixed oxide fuel fabrication facility

Takasaki, Koji; Sagawa, Naoki; Kurosawa, Shigeyuki*; Shioya, Satoshi; Suzuki, Kazunori; Horikoshi, Yoshinori; Mizuniwa, Harumi

JAEA-Technology 2008-028, 73 Pages, 2008/03

JAEA-Technology-2008-028.pdf:5.88MB

Recently, an imaging plate (IP) was developed. Pu analysis by an IP was studied in the JAEA Cooperative Research Scheme on the Nuclear Fuel Cycle, and the availability about detection of Pu and discrimination with radon progenies was shown. In order to apply these results to the radiation control, this research aims at evaluation of radioactivity, discrimination with radon progenies, and evaluation of AMAD by an IP. In the conventional autoradiography (ARG) by a ZnS and Polaroid film, Contamination of Pu can only be grasped by viewing. Since the digital data of the radiation and location is obtained by an IP, Pu can be detected quantitatively and radioactivity can be evaluated. As a result of this research, the image of alpha emitter on an IP is the same as that of the conventional ARG, and can be applied also to the ARG of beta and $$gamma$$ emitter. In measurement of Pu, the function of Image J (image-analysis software) was very available. Pu radioactivity was evaluated by an IP.

JAEA Reports

Study on investigation of microbial effects for geological disposal, 2 (Joint research)

Tochigi, Yoshikatsu; Yoshikawa, Hideki; Aoki, Kazuhiro; Yui, Mikazu; Asano, Takahiro*; Honjo, Hideko*; Haginuma, Masashi*; Kawakami, Yasushi*; Suzuki, Kazunori*

JAEA-Research 2008-025, 55 Pages, 2008/03

JAEA-Research-2008-025.pdf:8.55MB

Results of joint research on fiscal year 2006 between Japan Atomic Energy Agency (JAEA) and Institute of Research and Innovative (IRI) titled as "Study on investigation of microbial effects for geological disposal" are described in this report. The objective of this study is to develop a method for estimating microbial effects for barrier performance of geological disposal site. The modeling was performed to examine the effect on the change in groundwater chemistry (mainly by electron acceptors) by microbial metabolism as well as microbial activities. In order to use the data (chemical composition, biomass, etc.) in the MINT code, groundwater was collected from the drilled well prepared for chemical and microbial analyses of groundwater. The well was prepared in observation field near Horonobe Underground Research Center of JAEA in fiscal year 2006. Then, numerical modeling using collected data of groundwater with numerical modeling program code "MINT" considering microbial effects was carried out. The modeling was carried out to evaluate the microbial effect for stability of chemical and microbial composition of groundwater. As the result of the modeling, relatively low microbial effect for groundwater composition was observed in particular for the concentration of dissolved methane, methanogen, sulfur reducing bacteria (SRB) and sulfur ion. The result shows that low redox potential is stable in the well in spite of shallow depth.

Journal Articles

Leakage of water containing radioactive materials inside the controlled area of the experimental fast reactor Joyo

Ohara, Norikazu; Suzuki, Toshiaki; Isozaki, Kazunori

UTNL-R-0466, p.6_1 - 6_11, 2008/03

no abstracts in English

JAEA Reports

Study on investigation of microbial effects for geological disposal, 1 (Joint research)

Tochigi, Yoshikatsu; Yoshikawa, Hideki; Aoki, Kazuhiro; Yui, Mikazu; Honjo, Hideko*; Haginuma, Masashi*; Kawakami, Yasushi*; Suzuki, Kazunori*

JAEA-Research 2007-010, 51 Pages, 2007/03

JAEA-Research-2007-010.pdf:4.82MB

Results of joint research on Fiscal 2005 between Japan Atomic Energy Agency (JAEA) and Institute of Research and Innovative (IRI) titled as "Study for investigation of microbial effects on geological disposal" are described in this report. The objective of this study is constructing advanced method for examining microbial effect for barrier performance of geological disposal site. In fiscal 2005, groundwater and rock core sample have been collected from drilled well on observation field near Horonobe Underground Research Center of JAEA and chemical analysis for collected ground water have been carried out and sensitivity analysis for existing observed data of groundwater with numerical analysis program code "MINT" considering microbial effect have been carried out.

JAEA Reports

Report of investigation on malfunction of reserved shutdown system in HTTR

Hamamoto, Shimpei; Iigaki, Kazuhiko; Shimizu, Atsushi; Sawahata, Hiroaki; Kondo, Makoto; Oyama, Sunao; Kawano, Shuichi; Kobayashi, Shoichi; Kawamoto, Taiki; Suzuki, Hisashi; et al.

JAEA-Technology 2006-030, 58 Pages, 2006/03

JAEA-Technology-2006-030.pdf:10.69MB

During normal operation of High Temperature engineering Test Reactor (HTTR) in Japan Atomic Energy Agency (JAEA), the reactivity is controlled by the Control Rods (CRs) system which consists of 32 CRs (16 pairs) and 16 Control Rod Drive Mechanisms (CRDMs). The CR system is located in stand-pipes accompanied by the Reserved Shutdown System (RSS). In the unlikely event that the CRs fail to be inserted, the RSS is provided to insert B$$_{4}$$C/C pellets into the core. The RSS shall be designed so that the reactor should be held subcriticality from any operation condition by dropping in the pellets. The RSS consists of B$$_{4}$$C/C pellets, hoppers which contain the pellets, electric plug, driving mechanisms, guide tubes and so on. In accidents when the CRs cannot be inserted, an electric plug is pulled out by a motor and the absorber pellets fall into the core by gravity. A trouble, malfunction of one RSS out of sixteen, occurred during a series of the pre-start up checks of HTTR on February 21, 2005. We investigated the cause of the RSS trouble and took countermeasures to prevent the issue. As the result of investigation, the cause of the trouble was attributed to the following reason: In the motor inside, The Oil of grease of the multiplying gear flowed down from a gap of the oil seal which has been deformed and was mixed with abrasion powder of brake disk. Therefore the adhesive mixture prevented a motor from rotating.

Journal Articles

Development of continuous sintering equipment for MOX fuel fabrication

Yamada, Yoshikazu; Kurita, Ichiro; Suzuki, Kazunori; Shinada, Kenta; Kato, Mitsuaki*

Proceedings of International Conference on Nuclear Energy System for Future Generation and Global Sustainability (GLOBAL 2005) (CD-ROM), 5 Pages, 2005/10

None

JAEA Reports

Periodic Safety Review of the Experimental Fast Reactor JOYO; Review of Aging Management

Isozaki, Kazunori; Ogawa, Toru; Nishino, Kazunari; Kaito, Yasuaki; Ichige, Satoshi; Sumino, Kozo; Suto, Masayoshi; Kawahara, Hirotaka; Suzuki, Toshiaki; Takamatsu, Misao; et al.

JNC-TN9440 2005-003, 708 Pages, 2005/05

JNC-TN9440-2005-003.pdf:31.46MB

Periodic safety review (Review of the aging management) which consisted of Technical review on aging for the safety related structures, systems and components and Establish a long term maintenance program was carried out up to April 2005.1. Technical review on aging for the safety related structures, systems and components It was technically confirmed to prevent the loss of function of the safety related structures, systems and components due to aging phenomena, which (1) irradiation damage, (2) corrosion, (3) abrasion and erosion, (4) thermal aging, (5) creep and fatigue, (6) Stress Corrosion Cracking, (7) insulation deterioration and (8) general deterioration, under the periodic monitoring or renewal of them 2. Establish a long term maintenance program The long term maintenance program during JPY2005 to 2014 were established based on the technical review on aging for the safety related structures, systems and components. It was evaluated that the inspection or renewal based on the long term maintenance program, in addition to the spontaneous inspection long-term schedule of the long term voluntary inspection plan, could prevent the loss of function of the safety related structures, systems and components in future.

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