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Ono, Ayato; Takayanagi, Tomohiro; Sugita, Moe; Ueno, Tomoaki*; Horino, Koki*; Yamamoto, Kazami; Kinsho, Michikazu
JAEA-Technology 2022-036, 31 Pages, 2023/03
JAEA-Technology-2022-036.pdf:8.77MB
In the Japan Atomic Energy Agency (JAEA), many electrical facilities such as power receiving equipment and power supply units are installed in experimental facilities such as the Nuclear Science Research Institute (NSRI) and the Japan Proton Accelerator Research Complex (J-PARC). However, some facilities have been in operation for more than half a century since they were manufactured, some have already been closed or deactivated, and others are still in operation while replacing parts and taking other aging measures. In these facilities, materials that were used because of their excellent properties at the time of manufacture are now designated as hazardous substances and require special management when disposed of. One of them is polychlorinated biphenyl (PCB). PCB were used in a very wide range of fields because of their stability against heat, high electrical insulation, and chemical resistance. However, it was found that PCB have persistent properties and may cause damage to human health and the living environment, and the government has enacted the "Act on Special Measures for Promotion of Proper Treatment of PCB Wastes (PCB Special Measures Law)" to promote reliable and proper disposal. JAEA has almost completed the excavation survey of high-concentration PCB waste and is in the process of excavating low-concentration PCB waste. However, there are still new relevant items to be discovered. This report summarizes and reports the knowledge necessary for identifying PCB waste and points to be noted when handling capacitors, etc., based on examples of actual disassembly and investigation work conducted on power supply units and other electrical equipment, such as capacitors attached to power supply units, etc.
Np using graphite thermal columnNakamura, Shoji; Endo, Shunsuke; Kimura, Atsushi; Shibahara, Yuji*
KURNS Progress Report 2020, P. 94, 2021/08
The present study selected Np among radioactive nuclides and aimed to converge a contradiction between reported thermal-neutron capture cross sections. Neutron irradiation was carried out using the graphite thermal column equipped with the Kyoto University Research Reactor. A solution equivalent to 950 Bq order of radioactivity was pipetted out of a Np standard solution and dropped onto a fiber filter, which was then dried with an infrared lamp to prepare a Np sample. The Np sample was quantified using 312-keV gamma ray emitted from 
Pa in a radiation equilibrium with Np. To monitor a thermal-neutron flux component at an irradiation position, the Np sample was irradiated together with several stable nuclides as neutron flux monitors: 
Sc, 
Co, 
Mo, 
Ta and 
Au. The reaction rate of Np was obtained from gamma-ray yields given by 
Np and Pa, and then the thermal-neutron capture cross section of Np was derived.
Takada, Shoji; Ngarayana, I. W.*; Nakatsuru, Yukihiro*; Terada, Atsuhiko; Murakami, Kenta*; Sawa, Kazuhiko*
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 13 Pages, 2019/05
In the loss of core cooling test using HTTR, a technical issue is to improve prediction accuracy of temperature distribution of components in vessel cooling system (VCS). An establishment of reasonable 2D model was started by using numerical code FLUENT, which was validated using the test data by 1/6 scale model of VCS for HTTR. The pressure vessel (PV) temperature was set around 200
C attributed to relatively high ratio of natural convection heat transfer around 20% in total heat removal, which is useful for code to experiment benchmark to improve prediction accuracy. It is necessary to confirm heat transfer flow characteristics around the top of PV which is heated up by natural convection flow which was considered to be affected by separation, re-adhesion and transition flow. The k-
-SST model was selected for turbulent calculation attributed to predict the effects mentioned above adequately. The numerical results using the k--SST model reproduced the temperature distribution of PV especially the top region which is considered to be affected by separation, re-adhesion and transition flow in contract to that using k-
model which does not account the effects.
Hidaka, Akihide
Genshiryoku No Ima To Ashita, p.264 - 265, 2019/03
no abstracts in English
Sato, Junya; Kikuchi, Hiroshi*; Kato, Jun; Sakakibara, Tetsuro; Matsushima, Ryotatsu; Sato, Fuminori; Kojima, Junji; Nakazawa, Osamu
QST-M-8; QST Takasaki Annual Report 2016, P. 62, 2018/03
no abstracts in English
Kawabata, Kuniaki; Mori, Fumiaki*; Shirasaki, Norihito; Tanifuji, Yuta; Hanari, Toshihide
Proceedings of 2017 IEEE/SICE International Symposium on System Integration (SII 2017), p.450 - 455, 2018/02
This paper describes the test facilities and experimental environments for supporting the decommissioning of the nuclear facilities especially Fukushima Daiichi Nuclear Power Station by remote operation. Naraha Remote Technology Development Center of Japan Atomic Energy Agency is an institution for such purpose. Mock-up staircase, robot testing pool and motion capture arena are already installed and full service and support began from April, 2016. We are also designing and developing some experimental environment for remotely operated robots for nuclear decommissioning. In this paper, we describe current status and development of test facilities of Naraha Remote Technology Development Center, Japan Atomic Energy Agency.
Fujirai, Kosuke; Suganuma, Kazuaki; Yamazaki, Yoshio
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.874 - 876, 2017/12
The J-PARC (Japan Proton Accelerator Research Complex) 3-GeV RCS (Rapid Cycling Synchrotron) has many devices such as Radio-Frequency components, electromagnets and power supplies. These devices use 17MW of electricity during operation, most of which is consumed as thermal energy. Therefore, cooling water equipment is indispensable for the operation of the accelerator and its stability affects the operation rate of the accelerator. Due to resent operation experience, the bearing unit of the cooling tower fan, which is also an important part of the cooling water equipment, broke down. This accident leads to the suspension of the J-PARC operation. In order to investigate the cause of the failure, we tried to measure vibration for the defective bearing and the bearing unit were cut and observed damaged surface. As a result of the vibration measurement, it was found that vibration frequency depends on the presence or absence of scratches on the bearing. We found surface of the outer ring had scratches called flaking.
Saito, Hiroyuki*; Yamada, Yumi*; Oyama, Kazuhiro*; Matsunaga, Shoko*; Yamano, Hidemasa; Kubo, Shigenobu
Proceedings of 2017 International Congress on Advances in Nuclear Power Plants (ICAPP 2017) (CD-ROM), 10 Pages, 2017/04
A self-actuated shutdown system (SASS) is a passive device, which can detach a control rod for reactor shutdown in response to excessive increase in coolant temperature. Since a detachment temperature, which triggers release of a control rod, and a response time are identified as important parameters for validity analyses, this study focused on investigation of the response time and the detachment temperature, and safety analysis to see feasibility of the SASS in low power. For this purpose, design modifications were made to shorten the response time and three-dimensional thermal-hydraulic analysis in a low power operation was carried out in order to confirm the response time. The resulting detachment temperature level is lower than previous studies, leading to improved safety parameters. Based on improved parameters, a safety analysis to see feasibility of the SASS in low power was carried out. From this safety evaluation, it was confirmed that core damage can be prevented by the SASS with flow collector in the case of LOF type ATWS event.
Sakauchi, Hitoshi; Sato, Isamu*; Donomae, Yasushi; Kitamura, Ryoichi
JAEA-Technology 2015-059, 352 Pages, 2016/03
JAEA-Technology-2015-059.pdf:51.53MB
OWTF (Oarai Waste Reduction Treatment Facility) is constructed for volume reduction processing and stabilization treatment of 
solid waste, which was generated from hot facilities in Oarai Research and Develop Center of Japan Atomic Energy Agency, using in-can type high frequency induction heating by remote control. This report describes corroborative tests, in which incinerating and melting performance for OWTF is confirmed with a full-scale testing furnace. We have been carrying out the tests of incinerating and melting treatment with some kinds of simulated wastes, such as enclosure form of radioactive wastes, material and articles.
Matsumoto, Takashi; Morimoto, Yasuyuki; Takahashi, Nobuo; Takata, Masaharu; Yoshida, Hideaki; Nakashima, Shinichi; Ishimori, Yuu
JAEA-Technology 2015-036, 60 Pages, 2016/01
JAEA-Technology-2015-036.pdf:9.15MB
The Enrichment Engineering Facilities of the Ningyo-toge Environmental Engineering Center was constructed in order to establish the technical basis of the uranium enrichment plant in Japan. Uranium enrichment tests, using natural and reprocessed uranium, were carried out from 1979 to 1990 at two types of plants in the facilities. UF
handling equipment and Supplemental equipment in these plants are intended to be dismantled by 2019 in order to make places for future projects, for example, inventory investigation, precipitation treatment, etc. This report shows the basic plan of this decommissioning project and presents the current state of dismantling in the first-half of the fiscal year of 2014, with indicating its schedule, procedure, situation, results, and so on. The dismantled materials generated amounted to 37 mesh containers and 199 drums, and the secondary waste generated amounted to 271.4 kg.
Matsubara, Akihiro; Fujita, Natsuko; Miyake, Masayasu*; Nishizawa, Akimitsu*; Kokubu, Yoko
Dai-17-Kai AMS Shimpojiumu Hokokushu, p.40 - 45, 2015/12
no abstracts in English
Ebisawa, Noboru; Kiuchi, Shigeki*; Kikuchi, Katsumi*; Kawano, Katsumi; Isono, Takaaki
JAEA-Testing 2014-003, 37 Pages, 2015/03
JAEA-Testing-2014-003.pdf:11.7MB
Objective of the ITER CS Model Coil Test Facility is to evaluate a large scale superconducting conductor for fusion using the Central Solenoid (CS) Model Coil, which can generate a 13-T magnetic field in the inner bore with a 1.5m diameter. The facility is composed of a helium refrigerator / liquefier system, a DC power supply system, a vacuum system and a data acquisition system. This report describes that maintenance of the helium refrigerator / liquefier system since the Great East Japan Earthquake in March 2011 until the first operation after the earthquake in December 2012.
Takamatsu, Kuniyoshi; Hu, R.*
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 12 Pages, 2014/12
continuous closed regions; one is an ex-reactor pressure vessel (RPV) region and another is a cooling region having heat transfer area to ambient air assumed at 40 (C). The RCCS uses novel shape so that the heat released from the RPV can be removed efficiently with radiation and natural convection. Employing the air as the working fluid and the ambient air as the ultimate heat sink, the new RCCS design greatly reduces the possibility of losing the heat sink for decay heat removal. Therefore, HTGRs and VHTRs adopting the new RCCS design can avoid core melting owing to overheating the fuels.
Minato, Kazuo; Akabori, Mitsuo; Tsuboi, Takashi; Kurobane, Shiro; Hayashi, Hirokazu; Takano, Masahide; Otobe, Haruyoshi; Misumi, Masahiro*; Sakamoto, Takuya*; Kato, Isao*; et al.
JAERI-Tech 2005-059, 61 Pages, 2005/09
JAERI-Tech-2005-059.pdf:20.67MB
An experimental facility called the Module for TRU High Temperature Chemistry (TRU-HITEC) was installed in the Back-end Cycle Key Elements Research Facility (BECKY) of the Nuclear Fuel Cycle Safety Engineering Research Facility (NUCEF) for the basic studies of the behavior of the transuranium elements (TRU) in pyrochemical reprocessing and oxide fuels. TRU-HITEC consists of three alpha/gamma cells shielded by steel and polyethylene and a glove box shielded by leaded acrylic resin, where experimental apparatuses have been equipped and a high purity argon gas atmosphere is maintained. In the facility 10 g of 
Am as well as the other TRU of Np, Pu and Cm can be handled. This report summarizes the outline, structure, performance and interior apparatuses of the facility, and is the result of the joint research between the Japan Atomic Energy Research Institute and three electric power companies of Tokyo Electric Power Co., Tohoku Electric Power Co. and the Japan Atomic Power Co.
Tochio, Daisuke; Nakagawa, Shigeaki
JAERI-Tech 2005-041, 109 Pages, 2005/08
JAERI-Tech-2005-041.pdf:4.48MB
In High Temperature Engineering Test Reactor (HTTR) of 30MW, the generated heat at reactor core is finally dissipated at the air-cooler by way of the heat exchangers of the primary pressurized water cooler and the intermediate heat exchanger. To remove generated heat at reactor core and to hold reactor inlet coolant temperature to specified temperature, heat exchangers in main cooling system of HTTR should have designed heat exchange performance. In this report, heat exchange performance for ACL in main cooling system is evaluated with previous operation data, and evaluated values are compared with designed value. Moreover, heat exchange performance at full power operation is estimated for the air temperature. As the result, ACL has heat exchange performance removing generated heat at reactor core under the designe ACL inlet air temperature of 33C.
Akasaka, Hiromi; Takano, Shoji*; Kawamata, Yoichi; Yonekawa, Izuru
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
Sakata, Shinya; Kiyono, Kimihiro; Oshima, Takayuki; Sato, Minoru; Ozeki, Takahisa
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
no abstracts in English
Sato, Minoru; Kiyono, Kimihiro; Oshima, Takayuki; Sakata, Shinya; Ozeki, Takahisa; Matsuda, Toshiaki; Nagasaka, Yasushi*; Obata, Takayoshi*
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 3 Pages, 2005/03
no abstracts in English
Kiyono, Kimihiro; Oshima, Takayuki; Sakata, Shinya; Sato, Minoru; Ozeki, Takahisa; Matsuda, Toshiaki
Heisei-16-Nendo Osaka Daigaku Sogo Gijutsu Kenkyukai Hokokushu (CD-ROM), 4 Pages, 2005/03
State of JT-60 Data Processing System
Katanishi, Shoji; Kunitomi, Kazuhiko; Tsuji, Nobumasa*; Maekawa, Isamu*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.257 - 267, 2004/09
no abstracts in English
