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Kondo, Yasuhiro; Hirano, Koichiro; Ito, Takashi; Kikuzawa, Nobuhiro; Kitamura, Ryo; Morishita, Takatoshi; Oguri, Hidetomo; Okoshi, Kiyonori; Shinozaki, Shinichi; Shinto, Katsuhiro; et al.
Journal of Physics; Conference Series, 1350, p.012077_1 - 012077_7, 2019/12
Times Cited Count：1 Percentile：52.28(Physics, Particles & Fields)We have upgraded a 3-MeV linac at J-PARC. The ion source is same as the J-PARC linac's, and the old 30-mA RFQ is replaced by a spare 50-mA RFQ, therefore, the beam energy is 3 MeV and the nominal beam current is 50 mA. The main purpose of this system is to test the spare RFQ, but also used for testing of various components required in order to keep the stable operation of the J-PARC accelerator. The accelerator has been already commissioned, and measurement programs have been started. In this paper, present status of this 3-MeV linac is presented.
Fuwa, Yasuhiro; Shinozaki, Shinichi; Chishiro, Etsuji; Hirane, Tatsuya; Fang, Z.*; Fukui, Yuji*; Futatsukawa, Kenta*; Mizobata, Satoshi*; Iwama, Yuhei*; Sato, Yoshikatsu*; et al.
Proceedings of 16th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.611 - 613, 2019/10
In the J-PARC linac, a proton accelerator is operated using 45 units of 324 MHz and 972 MHz klystrons. In the future stabilization and advancement of the accelerator, it is important to acquire the klystron output characteristics near the maximum output accurately. In order to understand this characteristics, measurement of the characteristics of the replaced klystron for some reason such as discharge, as well as the new klystron. However, such measurements have not been performed because of the risk of damage including peripheral equipment due to discharge and the temporal interference with the operation of the accelerator. Therefore, we set up a klystron test stand in the linac building and measured the high-voltage characteristics and input/output characteristics of the klystron under various operating parameters. By using this measurement result, the characteristics of klystron can be obtained before installation, and it becomes possible to determine the optimum operation parameters and make effective plan of klystron replacements. In addition, basic data for predicting the degradation tendency of klystron was acquired by comparing the characteristics of the used and used klystron.
Futatsukawa, Kenta*; Fang, Z.*; Fukui, Yuji*; Shinozaki, Shinichi; Mizobata, Satoshi; Sato, Yoshikatsu*
Proceedings of 14th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.486 - 489, 2017/12
In the J-PARC linac, the LLRF systems consist of twenty-four 324-MHz systems and twenty-five 972-MHz systems for ACS cavities. The 324-MHz LLRF systems, which were installed in the stations of RFQ, DTLs, and SDTLs, have been used since the beginning of the J-PARC and are more than ten years into the development. Realistically speaking, the incensement of the failure frequency for these systems is expected. Additionally, it is difficult to maintain those for some discontinued boards of a digital feedback (DFB) and a digital feedforward (DFF) at cPCI, and the older OS and developing environment of software. Therefore, we are starting to study the new LLRF system of the next generation. In the present, we are exploring several possibilities of a new way and investigating each advantage and disadvantage. The project and the status of the development for the new system in the J-PARC linac LLRF are introduced.
Takayasu, Kentaro; Onuki, Kenji*; Kawamoto, Koji*; Takayama, Yusuke; Mikake, Shinichiro; Sato, Toshinori; Onoe, Hironori; Takeuchi, Ryuji
JAEA-Technology 2017-011, 61 Pages, 2017/06
JAEA-Technology-2017-011.pdf:9.15MB
The Groundwater REcovery Experiment in Tunnel (GREET) was put into effect as development of drift backfilling technologies. This test was conducted by making the Closure Test Drift (CTD) recovered with water after carrying out a plug around 40m distance from northern edge face of horizontal tunnel of depth 500m, for the purpose of investigation of recovering process of rock mass and groundwater under the influence of excavation of tunnel. This report presents the efforts of backfilling investigation using bentonite composite soil and execution of backfilling into borehole pits excavated in the CTD which were carried out in fiscal 2014 as a part of GREET, and succeeding observation results inside pits from September 2014 to March 2016.
Kondo, Yasuhiro; Asano, Hiroyuki*; Chishiro, Etsuji; Hirano, Koichiro; Ishiyama, Tatsuya; Ito, Takashi; Kawane, Yusuke; Kikuzawa, Nobuhiro; Meigo, Shinichiro; Miura, Akihiko; et al.
Proceedings of 28th International Linear Accelerator Conference (LINAC 2016) (Internet), p.298 - 300, 2017/05
We have constructed a linac for development of various accelerator components at J-PARC. The ion source is same as the J-PARC linac's, and the RFQ is a used one in the J-PARC linac. The beam energy is 3 MeV and nominal beam current is 30 mA. The accelerator has been already commissioned, and the first development program, laser-charge-exchange experiment for the transmutation experimental facility, has been started. In this paper, present status of this 3-MeV linac is presented.
Toguri, Satohito*; Kobayashi, Shinji*; Tsuji, Masakuni*; Yahagi, Ryoji*; Yamada, Toshiko*; Matsui, Hiroya; Sato, Toshinori; Mikake, Shinichiro; Aoyagi, Yoshiaki
JAEA-Technology 2017-005, 43 Pages, 2017/03
JAEA-Technology-2017-005.pdf:4.4MB
The study on engineering technology in the Mizunami Underground Research Laboratory (MIU) project roughly consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration and mitigating of the excavation effect. In FY2015, as a part of the important issues on the research program, water-tight grouting method has been developed. Grouting methods utilized in the MIU were evaluated and the post-excavation grouting at the -500m Access/Research Gallery-South was planned based on these evaluation results. Also, technology development from the viewpoint of geological disposal was summarized, and information on the alternative method to the grouting method was collected and organized.
Fukaya, Masaaki*; Takeda, Nobufumi*; Miura, Norihiko*; Ishida, Tomoko*; Hata, Koji*; Uyama, Masao*; Sato, Shin*; Okuma, Fumiko*; Hayagane, Sayaka*; Matsui, Hiroya; et al.
JAEA-Technology 2016-035, 153 Pages, 2017/02
JAEA-Technology-2016-035.pdf:37.6MB
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) project in FY2016, detailed investigations of the (mechanical) behaviors of the plug and the rock mass around the reflood tunnel through ongoing reflood test were performed as part of (5) development of technologies for restoration and/or reduction of the excavation damage. As the result, particularly for the temperature change of the plug, its analytical results agree fairly well agree with the measurement ones. This means cracks induced by temperature stress can be prevented by the cooling countermeasure works reviewed in designing stage. In addition, for the behaviors of the plug and the bedrock boundary after reflooding the reflood tunnel, comparison between the results obtained by coupled hydro-mechanical analysis (stress-fluid coupled analysis) with the ones by several measurements, concluded that the model established based on the analysis results is generally appropriated.
Tsuji, Masakuni*; Kobayashi, Shinji*; Mikake, Shinichiro; Sato, Toshinori; Matsui, Hiroya
Procedia Engineering, 191, p.543 - 550, 2017/00
Times Cited Count：11 Percentile：92.43(Mining & Mineral Processing)This paper shows the application of two post-grouting works to a gallery at 500 m depth of Mizunami Underground Research Laboratory in Japan. Three new grouting concepts were applied to the post-grouting works; a new grout material, a new injection system, and a new post-grouting zone. As for a grout material, "durable liquid-type colloidal silica grout (CSG)" was applied to seal the narrow fractures. As for an injection system, "complex dynamic grouting method" was applied to improve the penetrability of the grout material. The grouting works were successful in reducing the abundant water inflow from the rock mass with many fractures.
Futatsukawa, Kenta*; Kobayashi, Tetsuya*; Sato, Yoshikatsu; Shinozaki, Shinichi; Fang, Z.*; Fukui, Yuji*; Mizobata, Satoshi; Michizono, Shinichiro*
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.327 - 331, 2016/11
In the J-PARC linac, an intermediate-pulse with the comb-like structure is shaped by kicking an unwanted beam by the chopper cavity. Therefore, the cavities lying downstream of the RF-chopper have the beam loading with this beam shape. The present feedforward system which assumes the averaged beam current and not the comb-like beam was operated in the present LLRF, because the beam current in the linac was lower than the design value. However, it has been difficult that the required precision for the RF system is satisfied with increasing beam current. Thus, we performed the beam study of the beam loading compensation with the same shapes as the intermediate-pulses. The positive results for the cavities of SDTL and DTL with high Q values were obtained compared to the present system. On the other hand, when this compensation system was used in the case of ACS cavities, the neighbor modes were excited by the input RF. We have to improve the FF system for the operation against the real beam.
Hori, Toshihiko*; Shinozaki, Shinichi; Sato, Yoshikatsu; Mizobata, Satoshi; Fukui, Yuji*; Futatsukawa, Kenta*
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.429 - 432, 2016/11
The triode klystrons with a modulating anode have been used for the J-PARC linac. Recently, we exchanged four klystrons due to the frequent discharge at a modulating anode in the klystron tube. In order to understand the discharge mechanism and to estimate the time to replace the klystron, we need to monitor the long term performance of the klystron such as the degradation of a cathode emission current and the RF gain of the klystron tube and so on. Therefore, we started to develop the klystron perveance and gain monitor module (NIM Standard one). In this paper, we will present the design concept of the monitor module, and the first performance test result using the module prototype.
Hirano, Koichiro; Asano, Hiroyuki; Ishiyama, Tatsuya; Ito, Takashi; Okoshi, Kiyonori; Oguri, Hidetomo; Kondo, Yasuhiro; Kawane, Yusuke; Kikuzawa, Nobuhiro; Sato, Yoshikatsu; et al.
Proceedings of 13th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.310 - 313, 2016/11
We have used a beam scraper with the incident angle of 65deg to reduce the beam power deposition density in the MEBT between a 324 MHz RFQ and a 50-MeV DTL of the J-PARC linac. The 65
scraper was irradiated by the H
beam up to particle number of 1.47E22. We observed a lot of surface projections with several hundred micrometers high in the beam irradiation damage on the scraper by using the laser microscope. In order to study the limits of scrapers, we constructed a new 3 MeV linac at J-PARC. We will conduct the scraper irradiation test at the end of this year.
Tsuji, Masakuni*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro; Matsui, Hiroya
Proceedings of 8th Nordic Grouting Symposium, p.171 - 185, 2016/09
This paper presents the application of a durable liquid-type colloidal silica grout (CSG), to the great depth of the Mizunami Underground Research Laboratory (MIU). The CSG had been invented decades ago in Japan for the purpose of the ground improvement. A post-grouting experiment with the CSG carried out in 300 m depth of MIU confirmed its applicability and good durability at a great depth more than 3 years. Furthermore, a comparison study of applying the CSG between this experiment and a Swedish project indicated good applicability of the Swedish theoretical design to MIU. The CSG with the Swedish design were applied to the post-grouting campaign in a gallery at 500 m depth for further reducing water ingress and for developing the latest grouting methodology. The grouting was successful in reducing the abundant inflow from the rock with many fractures. The conductivity of the grouted rock mass of the latter fans is estimated to be lower than 10
m/s.
Fukaya, Masaaki*; Hata, Koji*; Akiyoshi, Kenji*; Sato, Shin*; Takeda, Nobufumi*; Miura, Norihiko*; Uyama, Masao*; Kaneda, Tsutomu*; Ueda, Tadashi*; Hara, Akira*; et al.
JAEA-Technology 2016-002, 195 Pages, 2016/03
JAEA-Technology-2016-002.pdf:46.3MB
JAEA-Technology-2016-002-appendix(CD-ROM).zip:16.11MB
The researches on examination of the plug applied to the future reflood test was conducted as a part of (5) development of technologies for restoration and/on reduction of the excavation damage relating to the engineering technology in the MIU (2014), specifically focused on (1) plug examination (e.g. functions, structure and material) and the quality control methods and (2) analytical evaluation of rock mass behavior around the plug through the reflood test. As the result, specifications of the plug were determined. These specifications should be able to meet requirements for the safety structure and surrounding rock mass against predicted maximum water pressure, temperature stress and seismic force, and for controlling the groundwater inflow, ensuring the access into the reflood gallery and the penetration performance of measurement cable. Also preliminary knowledge regarding the rock mass behavior around the plug after flooding the reflood gallery by installed plug was obtained.
Ishizawa, Akihiro*; Idomura, Yasuhiro; Imadera, Kenji*; Kasuya, Naohiro*; Kanno, Ryutaro*; Satake, Shinsuke*; Tatsuno, Tomoya*; Nakata, Motoki*; Nunami, Masanori*; Maeyama, Shinya*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 92(3), p.157 - 210, 2016/03
The high-performance computer system Helios which is located at The Computational Simulation Centre (CSC) in The International Fusion Energy Research Centre (IFERC) started its operation in January 2012 under the Broader Approach (BA) agreement between Japan and the EU. The Helios system has been used for magnetised fusion related simulation studies in the EU and Japan and has kept high average usage rate. As a result, the Helios system has contributed to many research products in a wide range of research areas from core plasma physics to reactor material and reactor engineering. This project review gives a short catalogue of domestic simulation research projects. First, we outline the IFERC-CSC project. After that, shown are objectives of the research projects, numerical schemes used in simulation codes, obtained results and necessary computations in future.
Kobayashi, Shinji*; Niimi, Katsuyuki*; Tsuji, Masakuni*; Yamada, Toshiko*; Aoyagi, Yoshiaki; Sato, Toshinori; Mikake, Shinichiro; Osawa, Hideaki
JAEA-Technology 2015-039, 170 Pages, 2016/02
JAEA-Technology-2015-039.pdf:37.73MB
The researches on engineering technology in the Mizunami Underground Research Laboratory (MIU) plan consists of (1) development of design and construction planning technologies, (2) development of construction technology, (3) development of countermeasure technology, (4) development of technology for security, and (5) development of technologies regarding restoration or reversal and mitigating of the excavation effect. To develop design and construction planning technologies, and countermeasure technology, the analysis of measured data during earthquake and seismic movement characteristics at deep underground, and the examination of grouting method were carried out. For the characteristics of earthquake ground motion, measurement data obtained by seismometers installed in the Mizunami Underground Laboratory were analyzed, and the comprehensive assessment of the relationship between the measurement data and the geological condition at each depth was performed. As for "Study on grouting method at deep underground ", post grouting was carried out and evaluated based on the Construction plan in FY2013. Furthermore, target of the future R&D was proposed.
Tsuji, Masakuni*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro
Dai-44-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koenshu (CD-ROM), p.359 - 364, 2016/01
Pre-excavation grouting of shafts and galleries has been conducted during the construction of Mizunami Underground Research Laboratory in the aspect of safe works and reducing the discharge treatment of the water inflow. The grouting methodology has been simultaneously studied and developed as there is less experience of grouting in low conductive rock with high water pressure, especially in Japan. After excavating GL.-500m gallery on the ventilation shaft side, a post-excavation grouting campaign was performed on a 16-meter section of the pre-grouted area. Three new options for the grouting design were adopted and found to be effective with sufficiently decreasing the water inflow into the gallery.
Sato, Toshinori; Mikake, Shinichiro; Miura, Norihiko*; Ishida, Tomoko*
Tonneru To Chika, 46(12), p.901 - 911, 2015/12
The Japan Atomic Energy Agency conducts studies and research associated with the excavation of underground research facility at the Mizunami Underground Research Laboratory in Mizunami City, Gifu Prefecture. The research laboratory is an underground facility consisting of two shafts and some drifts and excavation has currently extended to a depth of 500 m. One of in-situ experiments, groundwater recovery experiment to understand groundwater pressure and geochemical properties change due to groundwater flooded has been performed in the GL.-500m drift. This report contains the results of design work of concrete plug for groundwater recovery experiment. Structural analysis and thermal stress analysis were performed to check resistant ability to over 5 MPa. Measurement plan was also discussed in this report.
Hama, Katsuhiro; Mikake, Shinichiro; Ishibashi, Masayuki; Sasao, Eiji; Kuwabara, Kazumichi; Ueno, Tetsuro; Onuki, Kenji*; Beppu, Shinji; Onoe, Hironori; Takeuchi, Ryuji; et al.
JAEA-Review 2015-024, 122 Pages, 2015/11
JAEA-Review-2015-024.pdf:80.64MB
Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technical basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase III, as the Phase II was concluded for a moment with the completion of the excavation of horizontal tunnels at GL-500m level in February 2014. This report presents the results of the investigations, construction and collaboration studies in fiscal year 2014.
Hama, Katsuhiro; Takeuchi, Ryuji; Saegusa, Hiromitsu; Iwatsuki, Teruki; Sasao, Eiji; Mikake, Shinichiro; Ikeda, Koki; Sato, Toshinori; Osawa, Hideaki; Koide, Kaoru
JAEA-Review 2015-021, 27 Pages, 2015/10
JAEA-Review-2015-021.pdf:4.35MB
The Mizunami Underground Research Laboratory (MIU) project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of geological disposal technologies through investigations of the deep geological environment in the crystalline host rock (granite rock) at Mizunami City in Gifu Prefecture, central Japan. This report summarizes the research and development activities planned for fiscal year 2015 based on the MIU Master Plan updated in 2015 and so on. On the occasion of the reform of the entire JAEA organization in 2014, JAEA identified the critical issues on the geoscientific research program: "Development of modelling technologies for mass transport", "Development of drift backfilling technologies" and "Development of technologies for reducing groundwater inflow", based on the latest results of the synthesizing R&D. Investigations on those critical issues will be performed at the MIU in fiscal year 2015.
Tsuji, Masakuni*; Kobayashi, Shinji*; Sato, Toshinori; Mikake, Shinichiro
Proceedings of the ISRM Regional Symposium EUROCK 2015 & 64th Geomechanics Colloquium; Future Development of Rock Mechanics, p.35 - 41, 2015/10
Rock grouting has been an essential measure to reduce water ingress into the deep underground during the excavation of Mizunami Underground Research Laboratory project in Japan. This paper shows an overview of grouting works performed at a gallery of 120 m at 500 m depth. After completion of its excavation with the pilot borehole investigation and pre-grouting mainly by Super-fine Portland cement, the inflow from the whole gallery was 200-220 Liter/min within the requirement. Then, at a limited section of 16 m, post-grouting was performed with new designs, applying colloidal silica grout, complex dynamic grouting, and grouting outside of the pregrouted zone. These designs were effective and the inflow at the section reduced from 35 to 11 Liter/min. These experiences must be fruitful for advancing the present technology and there should have been potential for reducing further inflow if any of the new designs are applied from the pre-grouting phase.
