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Saito, Shigeru; Yamaguchi, Kazushi*; Yoshimoto, Hidemitsu*; Obayashi, Hironari; Sasa, Toshinobu
JAEA-Technology 2022-032, 51 Pages, 2023/03
JAEA-Technology-2022-032.pdf:4.51MB
In the Accelerator Driven System (ADS) being studied by the Japan Atomic Energy Agency (JAEA) for transmutation of long-lived radioactive waste, lead-bismuth eutectic alloy (LBE) is used as a spallation target and subcritical core coolant. A proton irradiation facility in J-PARC is considered to prepare a material irradiation database for ADS development. The proton irradiation facility is equipped with an LBE loop, which enables material irradiation tests in spallation environment under flowing LBE condition. The slow leakage of LBE is one of critical issue to use LBE safety. The slow leakage is caused by the biting slag and/or other materials at valve seal of drain valve. To solve this problem, JAEA examined the application of freeze-seal valve (FSV), which seal the piping by freezing LBE in specific position. Water-cooled and air-cooled freeze-seal valve test modules were fabricated, installed in the test section of the existing test stand for LBE technology development, and tested to confirm their operation and performance. As a result of the tests, it was confirmed that the water-cooled FSV test module worked well along to the design values. This report describes the outline and details of the test stand for LBE technology and each FSV test module, as well as the results of operation and performance verification tests.
Saito, Shigeru; Wan, T.*; Okubo, Nariaki; Obayashi, Hironari; Watanabe, Nao; Ohdaira, Naoya*; Kinoshita, Hidetaka; Yamaki, Kenichi*; Kita, Satoshi*; Yoshimoto, Hidemitsu*; et al.
JPS Conference Proceedings (Internet), 33, p.011041_1 - 011041_6, 2021/03
An Accelerator Driven System (ADS) for waste transmutation investigated in JAEA employs lead-bismuth eutectic (LBE) as a neutron production target material and coolant. The neutrons are to be produced via the spallation with 1.5 GeV proton beam injection. As materials irradiation data are important for ADS development, JAEA plans to construct an irradiation facility with LBE neutron production target in J-PARC. There are many technical issues on LBE for practical use. In JAEA, various R&Ds are being carried out. Concerning corrosion study, conditioning operation and functional tests of OLLOCHI started. Oxygen concentration control technology has also developing. In the large scale LBE loop experiment, the operation for steady state and transient experiments was performed by using IMMORTAL. In the area of instrument, development of ultrasonic flow meter and freeze seal valve are progressing as a key technology for the LBE loop system. Investigation of behavior of impurities in LBE, which is important for design of the irradiation facility, started. In this paper, the status of the LBE studies and experimental plan will be presented.
Obayashi, Hironari; Yoshimoto, Hidemitsu*; Kita, Satoshi*; Yamaki, Kenichi*; Wan, T.*; Saito, Shigeru; Sasa, Toshinobu
JPS Conference Proceedings (Internet), 33, p.011048_1 - 011048_6, 2021/03
Saito, Yoshimoto*; Hirano, Shinichi*; Nagaoka, Toru*; Amano, Yuki
Ecological Genetics and Genomics, 12, p.100042_1 - 100042_9, 2019/10
Culture-independent molecular techniques enable us to analyze microflora in various environments. Many uncultured prokaryotes have been detected by the molecular methods from extreme environments, including anaerobic, no light, high-pressure, and high temperature. Recently, microbial eukaryotes were also detected in deep-sea environments, suggesting that microbial eukaryotes can adapt to a wider range of environments than previously thought. Here, we performed a culture-independent analysis of eukaryotes from approximately -250 m depth in the Horonobe Underground Research Laboratory at Horonobe, Japan. Our results indicate that fungi are the dominant eukaryotic flora in deep sedimentary rocks of Horonobe. We detected a wide range of species, including Zygomycete, Basidiomycete, and Ascomycete fungi from the rocks. This study is the first report of eukaryotic diversity in deep subsurface sedimentary rocks.
Obayashi, Hironari; Yamaki, Kenichi; Kita, Satoshi; Yoshimoto, Hidemitsu; Wan, T.; Saito, Shigeru; Sasa, Toshinobu
Proceedings of 18th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-18) (USB Flash Drive), p.262 - 274, 2019/08
Construction of an experimental facility using LBE spallation target is under planning in the framework of J-PARC project to understand the compatibility of candidate ADS structural materials under flowing high temperature LBE environment with proton / neutron irradiation. We constructed a mock-up test loop, IMMORTAL to verify the feasibility of a primary cooling system in the target system. Including the layout considering remote maintainability, the same design as the actual JAEA's LBE target is reflected in most devices of IMMORTAL such as an electromagnetic pump (EMP), a heat exchanger and instrumentations. During the integrated tests, the individually developed devices of LBE loop system worked without significant malfunction. Several experimental data to verify the safety analysis model for LBE loop system using RELAP5-3D was acquired by simulation experiment of transient events such as beam over power and decrease of forced cooling.
Sasa, Toshinobu; Saito, Shigeru; Obayashi, Hironari; Sugawara, Takanori; Wan, T.; Yamaguchi, Kazushi*; Yoshimoto, Hidemitsu
NEA/CSNI/R(2017)2 (Internet), p.111 - 116, 2017/06
Japan Atomic Energy Agency (JAEA) proposes to reduce the environmental impact caused from high-level radioactive waste by using Accelerator-driven system (ADS). To realize ADS, JAEA plans to build the Transmutation Experimental Facility (TEF) within the framework of J-PARC project. For the JAEA-proposed ADS, lead-bismuth eutectic alloy (LBE) is adopted as a coolant for subcritical core and spallation target. By using TEF in J-PARC, we are planning to solve technical difficulties for LBE utilization by completion of the data for the design of ADS. The 250kW LBE spallation target will be located in TEF facility to prepare material irradiation database. Various R&Ds for important technologies required to build the facilities are investigated such as oxygen content control, instruments development, remote handling techniques for target maintenance, and spallation target design. The large scale LBE loops for 250kW target mock up and material corrosion studies are also manufactured and ready for various experiments. The latest status of 250kW LBE spallation target optimization will be described in the presentation.
Yoshimoto, Masahiro; Takeda, Osamu; Kawase, Masato; Yamazaki, Yoshio; Kinsho, Michikazu; Saito, Yoshio*; Kabeya, Zenzaburo*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3930 - 3932, 2010/05
At the 3 GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex), the scheme of H
charge exchange injection using stripping foils is adopted. The charge exchange system is composed of three stripping foil devices. The first stripping foil device, which converts the H
beam from the 181 MeV LINAC into the H beam, can replace the broken foil with new one in vacuum remotely and automatically. In September 2007, mechanical trouble with the first stripping foil device had occurred just before the RCS beam commissioning was started. The magnetic coupling of the transfer rod had been decoupled and the transfer rod had been broken which was caught in the vacuum gate valve. We studied the trouble cause, re-examined the structural design and the selection for the material, and then verified the specification from endurance tests with sample pieces. Then the improved device was installed in the ring in September 2008.
Ogiwara, Norio; Kinsho, Michikazu; Kamiya, Junichiro; Yamamoto, Kazami; Yoshimoto, Masahiro; Hikichi, Yusuke; Kanazawa, Kenichiro; Mio, Keigo; Takiyama, Yoichi; Suganuma, Kazuaki; et al.
Vacuum, 84(5), p.723 - 728, 2009/12
Times Cited Count：7 Percentile：30.19(Materials Science, Multidisciplinary)To minimize the radiation exposure during maintenance, it is necessary to compose the 3-GeV RCS vacuum system with reliable components which have long life time in such a high level of radiation. In addition, it is necessary to keep the operating pressure with beam in ultra high vacuum for suppressing the pressure instability. Thus we should think of not only the outgassing mainly due to ion desorption but also the pumping efficiency. From the above, the vacuum system was designed. The ring is divided by the isolation valves into 6 sections, which can be pumped down independently. For avoiding any eddy current loss ceramic ducts are used in the bending and focusing magnets. These ducts are connected to the Ti ducts, putting the Ti bellows between. Here, we adopt pure Ti as a material for the ducts and bellows because of its small residual radioactivity. The ring is evacuated with 20 ion pumps (0.7 m
/s) and 24 turbomolecular pumps (TMPs) (1.3 m/s), which are attached to the Ti ducts. The TMPs are used for not only rough pumping but also evacuation during the beam operation. Especially a collimator system for localizing beam losses in a restricted area is evacuated with the TMPs, because the outgassing from this region will be probably the largest. On the other hand, each arc section is pumped by 4 ion pumps and 2 TMPs. To realize the above system, we have developed some components such as large aperture ceramic ducts and TMPs with high radioactive-resistance, as well as several kinds of heat treatment to reduce the outgassing. Finally, we have realized the UHV without baking in the RCS and the beam operation has been succeeded until now.
Ogiwara, Norio; Kinsho, Michikazu; Kamiya, Junichiro; Yamamoto, Kazami; Suganuma, Kazuaki; Yoshimoto, Masahiro; Saito, Yoshio*
no journal, ,
Sugawara, Takanori; Yamaguchi, Kazushi; Obayashi, Hironari; Saito, Shigeru; Yoshimoto, Hidemitsu; Sasa, Toshinobu
no journal, ,
JAEA is planning to build a Transmutation Experimental Facility (TEF) for R&D on volume reduction and mitigation of harmfulness of high-level radioactive waste by using an Accelerator-Driven System (ADS). In the ADS Target Test Facility (TEF-T) of the TEF, a liquid lead-bismuth eutectic (LBE) target will be irradiated with a high-power (250 kW) proton beam, and irradiation effects on structural materials will be studied. On the other hand, LBE is corrosive, so it is necessary to control oxygen concentration in LBE adequately to protect structural materials from the corrosion. In order to control the oxygen concentration in LBE, it is required to develop an oxygen sensor to measure the oxygen concentration. JAEA tried to fabricate two-types of oxygen sensors (platinum type and bismuth type). As the result, it was confirmed that output voltage of the platinum type sensors was adequate in a wide temperature range.
Sasa, Toshinobu; Saito, Shigeru; Obayashi, Hironari; Wan, T.; Sugawara, Takanori; Kita, Satoshi*; Yamaki, Kenichi*; Yoshimoto, Hidemitsu*
no journal, ,
JAEA proposes the Partitioning and Transmutation Technology to reduce the environmental impact caused from high-level radioactive waste using Accelerator-driven system (ADS) which adopts lead-bismuth eutectic alloy (LBE) as a coolant for subcritical core and spallation target. To realize ADS, JAEA plans to construct the Transmutation Experimental Facility (TEF) within the framework of J-PARC project. By using TEF in J-PARC, it is planned to solve technical issues for safe application of LBE by completing the data to design LBE-cooled ADS. The 250kW LBE spallation target will be located in TEF facility to prepare material irradiation database by both proton and neutron injection in the temperature range for typical LBE-cooled ADS. Detailed design and optimization of the target as a reference target of TEF-T and various elemental technologies are investigated. The large scale LBE loops for mock up the spallation target and material corrosion studies are also manufactured and ready for various experiments. The latest status of 250kW LBE spallation target design works will be described in the presentation.
Sasa, Toshinobu; Saito, Shigeru; Obayashi, Hironari; Ariyoshi, Gen; Wan, T.*; Okubo, Nariaki; Ohdaira, Naoya*; Yamaki, Kenichi*; Kita, Satoshi*; Yoshimoto, Hidemitsu*
no journal, ,
Japan Atomic Energy Agency (JAEA) proposes to reduce the minor actinides by Partitioning and Transmutation Technology using Accelerator-driven system (ADS). To realize ADS, JAEA plans to locate Lead-Bismuth Eutectic alloy (LBE) spallation target in J-PARC. LBE spallation target will be used to solve technical issues for ADS design by preparing irradiation database. The 400 MeV - 250 kW proton beam can be used for ADS studies. The spallation target is optimized by thermal-hydraulic analysis and structural analysis to increase proton/neutron irradiation of ADS materials by sharply focused proton beam injection. The studies for elemental technologies such as a fully-remote target exchange procedure and freeze-sealed drain valve system are also performed and integrated into the design of LBE target. The latest design of the J-PARC LBE spallation target system will be presented.
