Okano, Masanori; Akiyama, Kazuki; Taguchi, Katsuya; Nagasato, Yoshihiko; Omori, Eiichi
Dekomisshoningu Giho, (57), p.53 - 64, 2018/03
The construction of Tokai Reprocessing Plant (TRP) was initiated in June 1971, and its hot test using spent fuel started in September 1977. Thereafter TRP had been operated to reprocess 1,140 tons of spent fuel for approximately 30 years until May 2007, according to the reprocessing contract with domestic electric power companies. JAEA announced a policy of TRP in report of JAEA reform plan published in September 2014. The policy shows that TRP will shift to a decommissioning stage by economic reasons. Based on the policy, application of approval for TRP decommissioning plan was submitted to Nuclear Regulation Authority (NRA) in June 2017. This plan provides basic guidelines such as procedures for decommissioning and specific activities for risk reduction, and implementation divisions of decommissioning, management of spent fuels and radioactive wastes, decommissioning budget, and decommissioning schedule. The process of TRP decommissioning is planned to continue for approximately 70 years until the release of controlled areas of approximately 30 facilities.
Shirai, Nobutoshi; Miura, Yasushi; Tachibana, Ikuya; Omori, Satoru; Wake, Junichi; Fukuda, Kazuhito; Nakano, Takafumi; Nagasato, Yoshihiko
JAEA-Technology 2016-007, 951 Pages, 2016/07
The periodic safety review of TRP is to confirm the safety activities and get effective additional measures the facility safety and its reliability. We implemented 4 items; for (1) evaluation of safety activity implementation, we confirmed we are adequately expanding its safety activities by the necessary documents and schemes. For (2) evaluation of status of safety activities reflecting the latest technical knowledges, we confirmed we reflect latest knowledges for improvement of safety and reliability. For (3) technical evaluation about aging degradation, we can keep the safety of the facilities important to safety and the sea discharge line, under assumption of the present maintenance, because of "focuses for aging degradation". For (4) planning measures about a 10-years-plan that the operator shall implement to keep the facility condition, by the technical evaluation, we found no additional safety plans into maintenance strategies.
Fukuda, Kazuhito; Tomioka, Kenichiro*; Omori, Satoru; Nakano, Takafumi; Nagasato, Yoshihiko
JAEA-Technology 2014-032, 566 Pages, 2014/11
The Periodic Safety Review of TRP is assessment of the validity of safety activities in order to get assurance for continuous operation by adding effective items to extract and to execute for TRP safety. We performed 4 items; for (1) evaluation of safety activity at TRP, as we confirmed organization was ordered and managed. For (2) evaluation of status of safety activities reflecting the latest knowledge, we confirmed improvement of safety was continued adequately reflecting from the experience for safety. For (3) technical review on aging for the safety related structures, systems and components, we evaluated the guaranty of safety under assumption of continuous maintenance till the next Periodic Safety Review. For (4) establishment of long term maintenance program, we found no additional activities into maintenance programs, however, for several installations we established a plan and utilized them for reliability.
Takahashi, Yoshikazu; Nabara, Yoshihiro; Ozeki, Hidemasa; Hemmi, Tsutomu; Nunoya, Yoshihiko; Isono, Takaaki; Matsui, Kunihiro; Kawano, Katsumi; Oshikiri, Masayuki; Uno, Yasuhiro; et al.
IEEE Transactions on Applied Superconductivity, 24(3), p.4802404_1 - 4802404_4, 2014/06
Japan Atomic Energy Agency (JAEA) is procuring all amounts of NbSn conductors for Central Solenoid (CS) in the ITER project. Before start of mass-productions, the conductor should be tested to confirm superconducting performance in the SULTAN facility, Switzerland. The original design of cabling twist pitches is 45-85-145-250-450 mm, called normal twist pitch (NTP). The test results of the conductors with NTP was that current shearing temperature (Tcs) is decreasing due to electro-magnetic (EM) load cycles. On the other hand, the results of the conductors with short twist pitches (STP) of 25-45-80-150-450 mm show that the Tcs is stabilized during EM load cyclic tests. Because the conductors with STP have smaller void fraction, higher compaction ratio during cabling is required and possibility of damage on strands increases. The technology for the cables with STP was developed in Japanese cabling suppliers. The several key technologies will be described in this paper.
Nihon Genshiryoku Gakkai-Shi ATOMO, 55(11), p.661 - 662, 2013/11
no abstracts in English
Osamura, Kozo*; Machiya, Shutaro*; Tsuchiya, Yoshinori*; Suzuki, Hiroshi; Shobu, Takahisa; Sato, Masugu*; Hemmi, Tsutomu; Nunoya, Yoshihiko; Ochiai, Shojiro*
Superconductor Science and Technology, 25(5), p.054010_1 - 054010_9, 2012/05
Isono, Takaaki; Tsutsumi, Fumiaki; Nunoya, Yoshihiko; Matsui, Kunihiro; Takahashi, Yoshikazu; Nakajima, Hideo; Ishibashi, Tatsuji*; Sato, Go*; Chida, Keiji*; Suzuki, Rikio*; et al.
Teion Kogaku, 47(3), p.147 - 152, 2012/03
no abstracts in English
Baba, Hiromi*; Onizuka, Yoshihiko*; Nakao, Minoru*; Fukahori, Mai*; Sato, Tatsuhiko; Sakurai, Yoshinori*; Tanaka, Hiroki*; Endo, Satoru*
Radiation Protection Dosimetry, 143(2-4), p.528 - 532, 2011/02
The PHITS simulation were performed to reproduce the geometrical setup of an experiment that measured the microdosimetric energy distributions at the Kyoto University Reactor (KUR) where two types of tissue equivalent proportional counters (TEPC) were used, one with A-150 wall alone and another with a 50 ppm boron loaded A-150 wall. It was found that the PHITS code is a useful tool for the simulation of the energy deposited in tissue in BNCT based on the comparisons with experimental results.
Koyama, Shinichi; Ozawa, Masaki; Kurosawa, Kiyoko*; Tatenuma, Katsuyoshi*; Sato, Yoshihiko*; Okada, Ken*
Journal of Radioanalytical and Nuclear Chemistry, 286(3), p.807 - 813, 2010/12
A multi-functional separation process is proposed on the Adv.-ORIENT cycle concept. In this process, hydrochloric acid, mixture of nitric acid and methanol should be used as eluents. Two important subjects should be solved so as to prove the availability. One is corrosion aspect for the use of HCl solution, Tantalum was anti-corrosive in HCl media, and Hastelloy-B seemed to be acceptable at RT, with evidence of low corrosion rate ( 0.1 mm/y). The other is explication of the reactive safety between ion exchange resin and solvent (nitric acid and methanol). The reaction occurred regardless of nitric acid concentration and presence or absence of methanol when the temperature of heater reached 220 C. However, it was confirmed that the reaction did not occur when the heating temperature decreased.
Sato, Yoshihiko*; Okada, Ken*; Akiyoshi, Miyako*; Matsunaga, Takehiro*; Suzuki, Tatsuya*; Koyama, Shinichi; Ozawa, Masaki
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.962 - 969, 2009/09
The fundamental thermochemical properties of tertiary pyridine resin (TPR) and its mixtures with methanol/HCl and HNO were investigated and heating tests on gram scale with TPR/methanol/HNO were carried out. It was found that TPR with HCl was thermally stable. Evident thermal decomposition peaks were identified with TPR in the presence of concentrated HNO. No specific effect was observed for methanol involving. However, it was considered that the rapidly exothermic reaction can be controlled by heating temperature.
Tanimura, Yoshihiko; Sato, Tatsuhiko; Kumada, Hiroaki; Terunuma, Toshiyuki*; Sakae, Takeji*; Harano, Hideki*; Matsumoto, Tetsuro*; Suzuki, Toshikazu*; Matsufuji, Naruhiro*
Hoshasen, 34(2), p.135 - 139, 2008/04
Recently the traceability system (JCSS) of neutron standard based on the Japanese law "Measurement Act" has been instituted. In addition, importance of the neutron dose evaluation has been increasing in not only the neutron capture medical treatment but also the proton or heavy particle therapy. Against such a background, a symposium "Neutron dosimetry in neutron fields; From detection techniques to medical applications" was held on March 29, 2008 and recent topics on the measuring instruments and their calibration, the traceability system, the simulation technique and the medical applications were introduced. This article summarizes the key points in the discussion at the symposium.
Endo, Satoru*; Tanaka, Kenichi*; Takada, Masashi*; Onizuka, Yoshihiko*; Miyahara, Nobuyuki*; Sato, Tatsuhiko; Ishikawa, Masayoshi*; Maeda, Naoko*; Hayabuchi, Naofumi*; Shizuma, Kiyoshi*; et al.
Medical Physics, 34(9), p.3571 - 3578, 2007/09
Absorbed doses from main charged particle beams and charged-particle fragments have been measured with high accuracy for particle therapy but there are few reports for doses from neutron components produced as fragments. This study describes measurements on neutron dose produced by carbon beam, microdosimetric distributions of secondary neutrons produced by 290 MeV/nucleon carbon beams have been measured by using a tissue equivalent proportional counter (TEPC) at the Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Sciences (NIRS). The ratios of neutrons to charged particle fragments dominated to be 11 to 89 % in the absorbed doses at the side and below the faces of the acrylic phantom (300 mm height 300 mm width 253 mm thickness).
Ninomiya, Hiromasa; Akiba, Masato; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hayashi, Nobuhiko; Hosogane, Nobuyuki; Ikeda, Yoshitaka; Inoue, Nobuyuki; et al.
Journal of the Korean Physical Society, 49, p.S428 - S432, 2006/12
To contribute DEMO and ITER, the design to modify the present JT-60U into superconducting coil machine, named National Centralized Tokamak (NCT), is being progressed under nationwide collaborations in Japan. Mission, design and strategy of this NCT program is summarized.
Tsuzuki, Kazuhiro; Kamiya, Kensaku; Shinohara, Koji; Bakhtiari, M.*; Ogawa, Hiroaki; Kurita, Genichi; Takechi, Manabu; Kasai, Satoshi; Sato, Masayasu; Kawashima, Hisato; et al.
Nuclear Fusion, 46(11), p.966 - 971, 2006/11
no abstracts in English
Yagai, Tsuyoshi*; Sato, Hidenari*; Tsuda, Makoto*; Hamajima, Takataro*; Nunoya, Yoshihiko; Takahashi, Yoshikazu; Okuno, Kiyoshi
IEEE Transactions on Applied Superconductivity, 16(2), p.835 - 838, 2006/06
AC losses in the CIC conductor consist of both regular loss that are proportional to cable twisting pitch squared and irregular loss that could not be estimated from short conductor sample results. It was explained from our previous works that irregular loops produce the losses with long time constants up to several hundred seconds. The observed long time constant indicates that contact conditions between the two strands forming the loop should be line contact. We traced the sample conductor with 1 m in length. The measured results show that large displacements of strands from their original positions due to compressing the conductor provide many line contacts. It is found that the averaged line contact length reaches about 10 mm that is three orders of magnitude larger than the 0.01 mm of point contact length.
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
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.
Tsuchiya, Katsuhiko; Akiba, Masato; Azechi, Hiroshi*; Fujii, Tsuneyuki; Fujita, Takaaki; Fujiwara, Masami*; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; et al.
Fusion Engineering and Design, 81(8-14), p.1599 - 1605, 2006/02
no abstracts in English
Kasai, Satoshi*; Kamiya, Kensaku; Shinohara, Koji; Kawashima, Hisato; Ogawa, Hiroaki; Uehara, Kazuya; Miura, Yukitoshi; Okano, Fuminori; Suzuki, Sadaaki; Hoshino, Katsumichi; et al.
Fusion Science and Technology, 49(2), p.225 - 240, 2006/02
The diagnostic system of JFT-2M has consisted of about 30 individual diagnostic instruments,which were used to study the plasma production, control, equilibrium, stability, confinement, plasma heating by NBI and/or RF (LH, ICRF, ECH) and current drive by RF. In these instruments, the motional Stark effect (MSE) polarimeter, charge exchanged recombination spectroscopy (CXRS), heavy-ion beam probe (HIBP), time of flight (TOF) neutral particle analyzer, etc. have contributed to make clear the improved mechanism of confinement such as H-mode and High Recycling Steady (HRS) H-mode, and to search the operational region of these modes.The infrared TV camera system and lost ion probe have played a very important role to investigate the heat load onto the walls due to ripple loss particles and escaping ions from core plasma, respectively.
Tsuzuki, Kazuhiro*; Kimura, Haruyuki; Kusama, Yoshinori; Sato, Masayasu; Kawashima, Hisato; Kamiya, Kensaku; Shinohara, Koji; Ogawa, Hiroaki; Uehara, Kazuya; Kurita, Genichi; et al.
Fusion Science and Technology, 49(2), p.197 - 208, 2006/02
no abstracts in English
Tamai, Hiroshi; Akiba, Masato; Azechi, Hiroshi*; Fujita, Takaaki; Hamamatsu, Kiyotaka; Hashizume, Hidetoshi*; Hayashi, Nobuhiko; Horiike, Hiroshi*; Hosogane, Nobuyuki; Ichimura, Makoto*; et al.
Nuclear Fusion, 45(12), p.1676 - 1683, 2005/12
Design studies are shown on the National Centralized Tokamak facility. The machine design is carried out to investigate the capability for the flexibility in aspect ratio and shape controllability for the demonstration of the high-beta steady state operation with nation-wide collaboration, in parallel with ITER towards DEMO. Two designs are proposed and assessed with respect to the physics requirements such as confinement, stability, current drive, divertor, and energetic particle confinement. The operation range in the aspect ratio and the plasma shape is widely enhanced in consistent with the sufficient divertor pumping. Evaluations of the plasma performance towards the determination of machine design are presented.