Koga, Kazuhiro*; Suzuki, Kazunori*; Takagi, Tsuyohiko; Hamano, Tomoharu
FAPIG, (196), p.8 - 15, 2020/01
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.
Tsuruga Comprehensive Research and Development Center
JAEA-Technology 2019-007, 159 Pages, 2019/07
This report summarizes the history and achievements of the prototype fast breeder reactor Monju. The development of Monju started in 1968 as a prototype reactor following the experimental fast reactor Joyo. The development covers all the activity related to the fast reactor; plant design, mockup tests, construction, operation, and plant management. This report summarizes the history and achievements for 11 technical areas: history and principal achievements, design and construction, operation test, plant safety, core physics, fuel, plant system, sodium technology, materials and mechanical design, plant management, and trouble management.
Takano, Kazuya; Maruyama, Shuhei; Hazama, Taira; Usami, Shin
Proceedings of Reactor Physics Paving the Way Towards More Efficient Systems (PHYSOR 2018) (USB Flash Drive), p.1725 - 1735, 2018/04
Irradiation dependence of the core excess reactivity was investigated for the Monju system startup tests at zero-power carried out in 2010. The excess reactivity basically decreases with the decay of Pu in zero-power operation. However, the excess reactivity little changed in the two month period of the startup tests, which suggests a positive reactivity insertion during the period. The investigated irradiation dependence shows that the positive reactivity increases with reactor operation and mostly saturates by the fission-dose attained during the Monju zero-power operation in a month (10 fissions/cm). The saturated positive reactivity is equivalent to approximately 47% of the initially accumulated self-irradiation damage recovery assuming the defects were recovered by the fission-fragment irradiation in the reactor operation.
Ichikawa, Shoichi; Chiba, Yusuke; Ono, Fumiyasu; Hatori, Masakazu; Kobayashi, Takanori; Uekura, Ryoichi; Hashiri, Nobuo*; Inuzuka, Taisuke*; Kitano, Hiroshi*; Abe, Hisashi*
JAEA-Research 2016-021, 32 Pages, 2017/02
In order to reduce the influence on a plant schedule of the MONJU by the maintenance of dew point hygrometers, The JAEA examined a capacitance type dew point hygrometer as an alternative dew point hygrometer for a lithium-chloride type dew point hygrometer which had been used at the CV-LRT in the MONJU. As a result of comparing a capacitance type dew point hygrometer with a lithium-chloride type dew point hygrometer at the CV-LRT (Atmosphere: nitrogen, Testing time: 24 hours), there weren't significant difference between a capacitance type dew point hygrometer and a lithium-chloride type dew point hygrometer. As a result of comparing a capacitance dew point hygrometer with a high-mirror-surface type dew point hygrometer for long term verification (Atmosphere: air, Testing time: 24 months), the JAEA confirmed that a capacitance type dew point hygrometer satisfied the instrument specification (2.04C) required by the JEAC4203-2008.
Nakamura, Makoto; Tobita, Kenji; Someya, Yoji; Uto, Hiroyasu; Sakamoto, Yoshiteru; Gulden, W.*
Nuclear Fusion, 55(12), p.123008_1 - 123008_7, 2015/12
Major in- and ex-vessel loss-of-coolant accidents (LOCAs) of a water-cooled tokamak fusion DEMO reactor have been analysed. Analyses have identified responses of the DEMO systems to these accidents and pressure loads to confinement barriers for radioactive materials. The thermohydraulic analysis results suggests that the in- and ex-vessel LOCAs crucially threaten integrity of the primary and final confinement barriers, respectively. As for the in-vessel LOCA, it was found that the pressure in the vacuum vessel reaches its design value due to the LOCA even though a pressure suppression system is in service. As for the ex-vessel LOCA, the pressure load to the tokamak hall due to the double-ended break of the primary cooling pipe was found to be so large that integrity of the hall was crucially challenged. Mitigations of the loads to the confinement barriers are also discussed.
Nakamichi, Masaru; Kim, Jae-Hwan
Fusion Engineering and Design, 98-99, p.1838 - 1842, 2015/10
Advanced neutron multipliers with high stability at high temperatures are desired for the pebble bed blankets of DEMO reactors. Beryllium intermetallic compounds (beryllides) are the most promising material for this purpose. To fabricate the beryllide pebbles, a new granulation process has been established that combines a plasma sintering method for beryllide synthesis and a rotating electrode method using a plasma-sintered electrode for granulation. In granulation examinations, prototypic pebbles 1 mm in diameter of Be-V beryllide as well as Be-Ti beryllide were successfully fabricated. This study performed not only granulation of binary beryllides but also its characterization of the hydrogen generation reaction with water vapor compared with those of pure Be pebbles.
Kato, Shinya; Shimomoto, Yoshihiko; Kato, Yuko; Kitano, Akihiro
JAEA-Technology 2014-043, 36 Pages, 2015/02
The core management and operation code system aims to perform core management task efficiently by systematic management of data, analyses and edits, which are needed in the reactor core management and operation. The system consists of the five calculation modules: the reactor constant generation module, the neutronic-thermal calculation module, the radiation analysis module, the core structural integrity estimation module, and the core operation analysis module. In these modules, the neutronic-thermal calculation module is based on the dedicated three-dimensional diffusion and burn-up code HIZER. HIZER can execute core calculations easily for specific design specification and operation patterns of Monju, enabling efficient and accurate evaluation of the Monju core characteristics. This report describes its calculation method and validation results.
Advisory Committee on Monju Safety Requirements
JAEA-Evaluation 2014-005, 275 Pages, 2014/11
In July 2013, Nuclear Regulation Authority (NRA) has enforced new regulatory requirements in consideration of severe accidents for the commercial light water reactors (LWR) and also prototype power generation reactors such as the sodium-cooled fast reactors (SFR) of "Monju" based on TEPCO Fukushima Daiichi Nuclear Power Plant accident occurred in March 2011. Although the regulatory requirements for SFR will be revised by NRA with consideration for public comments, Japan Atomic Energy Agency (JAEA) set up "Advisory Committee on Monju Safety Concept" consists of fast breeder reactor (FBR) and safety assessment experts in order to establish original safety requirements expected to prototype FBR "Monju" considering severe accidents with knowledge from JAEA as well as scientific and technical insights from the experts. This report summarizes the safety requirements expected to Monju discussed by the committee.
Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Hoashi, Eiji*; Fukada, Satoshi*; Suzuki, Akihiro*; Yagi, Juro*; Tsuji, Yoshiyuki*; et al.
Proceedings of Plasma Conference 2014 (PLASMA 2014) (CD-ROM), 2 Pages, 2014/11
In the IFMIF/EVEDA (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activity), the validation tests of the EVEDA lithium test loop with the world's highest flow rate of 3000 L/min was succeeded in generating a 100 mm-wide and 25 mm-thick free-surface lithium flow steadily under the IFMIF operation condition of a high-speed of 15 m/s at 250C in a vacuum of 10 Pa. Some excellent results of the recent engineering validations including lithium purification, lithium safety, and remote handling technique were obtained, and the engineering design of lithium facility was also evaluated. These results will advance greatly the development of an accelerator-based neutron source to simulate the fusion reactor materials irradiation environment as an important key technology for the development of fusion reactor materials.
Nakamura, Makoto; Tobita, Kenji; Someya, Yoji; Tanigawa, Hisashi; Gulden, W.*; Sakamoto, Yoshiteru; Araki, Takao*; Watanabe, Kazuhito*; Matsumiya, Hisato*; Ishii, Kyoko*; et al.
Plasma and Fusion Research (Internet), 9, p.1405139_1 - 1405139_11, 2014/10
Key aspects of the safety study of a water-cooled fusion DEMO reactor is reported. Safety requirements, dose target, DEMO plant model and confinement strategy of the safety study are briefly introduced. The internal hazard of a water-cooled DEMO, i.e. radioactive inventories, stored energies that can mobilize these inventories and accident initiators and scenarios, are evaluated. It is pointed out that the enthalpy in the first wall/blanket cooling loops, the decay heat and the energy potentially released by the Be-steam chemical reaction are of special concern for the water-cooled DEMO. An ex-vessel loss-of-coolant of the first wall/blanket cooling loop is also quantitatively analyzed. The integrity of the building against the ex-VV LOCA is discussed.
Nakamura, Makoto; Ibano, Kenzo*; Tobita, Kenji; Someya, Yoji; Tanigawa, Hisashi; Gulden, W.*; Ogawa, Yuichi*
Proceedings of 25th IAEA Fusion Energy Conference (FEC 2014) (CD-ROM), 8 Pages, 2014/10
Of late in Japan, a design study has been undertaken of a tokamak fusion DEMO with pressurized water coolant and solid pebble bed breeding blanket, but safety characteristics of this type of DEMO have not been well examined. In this paper, thermohydraulics analysis of in-vessel and ex-vessel loss-of-coolant accidents of a water-cooled tokamak DEMO is reported. Safety characteristics of water-cooled DEMO, particularly possible loads onto confinement barriers, are discussed based on the thermohydraulics analysis results. Measures to reduce such loads are also proposed.
Ishii, Yasutomo; Matsunaga, Go
Purazuma, Kaku Yugo Gakkai-Shi, 90(10), p.641 - 643, 2014/10
Loading of the dust from JET (Joint European Torus) to DEMO R&D Building, holding of the joint research joint meeting regarding the BA prototype reactor design and safety, and the progress of the satellite tokamak (JT-60SA) plan are reported. The test sample, carbon and beryllium tiles coated tungsten on the surface, obtained in ITER simulated driving that performed in JET was brought into DEMO R&D building, Rokkasho Institute on August 18, 2014. Preparation of materials analysis has started. The joint research joint meeting of the BA prototype reactor design and safety was held in Rokkaho on July 30-31st. A lively discussion about the current situation and individual design task of Japan-EU prototype reactor design research has taken place. In addition to the JT-60SA tokamak body, the development of heating devices are also progressing well in Naka. To disseminate information to the domestic community a major event in the BA activities.
Fast Breeder Reactor Research and Development Center, Tsuruga Head Office
JAEA-Review 2014-030, 138 Pages, 2014/08
The prototype fast breeder reactor Monju has accumulated technical achievements in order to establish the fast breeder reactor cycle technology in Japan using the operation and maintenance experience, etc. This annual report summarizes the primary achievements and the data related to the plant management in Monju during fiscal 2013.
Tsuchiya, Kunihiko; Uchida, Munenori*; Kawamura, Hiroshi
Fusion Engineering and Design, 81(8-14), p.1057 - 1063, 2006/02
no abstracts in English
Ogawa, Hiroaki; Yamauchi, Yuji*; Tsuzuki, Kazuhiro; Kawashima, Hisato; Sato, Masayasu; Shinohara, Koji; Kamiya, Kensaku; Kasai, Satoshi; Kusama, Yoshinori; Yamaguchi, Kaoru*; et al.
Journal of Nuclear Materials, 329-333(Part1), p.678 - 682, 2004/08
no abstracts in English
Uchida, Munenori*; Uda, Minoru*; Iwadachi, Takaharu*; Nakamichi, Masaru; Kawamura, Hiroshi
Journal of Nuclear Materials, 329-333(Part2), p.1342 - 1346, 2004/00
In this paper, an elemental technology to fabricate beryllide rods by the vacuum casting was researched. Furnace material study to prevent the chemical reaction with beryllide and casting procedure study to cast durable ingot without any shrinkages and cracks were performed. From the results of the reactivity test of refractory material with BeTi, it was clear that the BeO crucible had less reactivity with melt and no contamination. From the results of casting tests with a MgO cylindrical mold in a vacuum chamber, it was revealed that the mold dimension was critical to minimize shrinkages and cracks. It was also found that the forced cooling by the MgO cylindrical sleeve with water-cooled copper mold on the bottom was efficient to improve the shrinkages and the cracks.
Uchida, Munenori*; Ishitsuka, Etsuo; Kawamura, Hiroshi
Fusion Engineering and Design, 69(1-4), p.499 - 503, 2003/09
no abstracts in English
Kurihara, Ryoichi; Watanabe, Kenichi*; Konishi, Satoshi
JAERI-Review 2003-020, 37 Pages, 2003/07
no abstracts in English
Ishida, Shinichi; Abe, Katsunori*; Ando, Akira*; Chujo, T.*; Fujii, Tsuneyuki; Fujita, Takaaki; Goto, Seiichi*; Hanada, Kazuaki*; Hatayama, Akiyoshi*; Hino, Tomoaki*; et al.
Nuclear Fusion, 43(7), p.606 - 613, 2003/07
no abstracts in English
Konishi, Satoshi; Nishio, Satoshi; Tobita, Kenji; DEMO Design Team
Fusion Engineering and Design, 63-64, p.11 - 17, 2002/12
The first fusion power plant DEMO must have some reality that ITER and other facilities in the same period are expected to prove its feasibility. The DEMO should also be so attractive and advanced that the future society would be interested in constructing based on its concept. The present DEMO plant concept intends to satisfy these antagonistic requirements assuming construction in 2030s immediately after successful completion of fundamental ITER mission. A steady tokamak is minimized to have 5.8m of major radius with 2.3GW with Q exceeds 30. Modestly ambitious plasma parameters are chosen. Technology improvement is assumed to make maximum 20 T magnet, metal first wall and super critical water cooled ITER-like blanket modules feasible. Tritium inventory is reduced to 1kg with improved safety system concept. This conceptual design identifies various technical issues that are expected to be solved by intensive R&D efforts during ITER period, and indicates a possible step immediately after ITER.