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Yamamoto, Kazami; Kinsho, Michikazu; Hayashi, Naoki; Saha, P. K.; Tamura, Fumihiko; Yamamoto, Masanobu; Tani, Norio; Takayanagi, Tomohiro; Kamiya, Junichiro; Shobuda, Yoshihiro; et al.
Journal of Nuclear Science and Technology, 59(9), p.1174 - 1205, 2022/09
Times Cited Count：6 Percentile：84.97(Nuclear Science & Technology)In the Japan Proton Accelerator Research Complex, the purpose of the 3 GeV rapid cycling synchrotron (RCS) is to accelerate a 1 MW, high-intensity proton beam. To achieve beam operation at a repetition rate of 25 Hz at high intensities, the RCS was elaborately designed. After starting the RCS operation, we carefully verified the validity of its design and made certain improvements to establish a reliable operation at higher power as possible. Consequently, we demonstrated beam operation at a high power, namely, 1 MW. We then summarized the design, actual performance, and improvements of the RCS to achieve a 1 MW beam.
Nasu, Mitsunori*; Yanai, Hiroshi*; Hirayama, Naoki*; Adachi, Hironori*; Kakizawa, Yu*; Shirase, Yuto*; Nishiyama, Hiromichi*; Kawamoto, Teppei*; Inukai, Junji*; Shinohara, Takenao; et al.
Journal of Power Sources, 530, p.231251_1 - 231251_11, 2022/05
Times Cited Count：16 Percentile：89.77(Chemistry, Physical)Takiya, Hiroaki; Kadowaki, Haruhiko; Matsushima, Akira; Matsuo, Hidehiko; Ishiyama, Masahiro; Aratani, Kenta; Tezuka, Masashi
JAEA-Technology 2020-001, 76 Pages, 2020/05
JAEA-Technology-2020-001.pdf:6.06MB
Advanced Thermal Reactor (ATR) FUGEN was operated for about 25 years, and now has been proceeding decommissioning after the approval of the decommissioning plan in Feb. 2008. The reactor, heavy water system and helium system are contaminated by tritium because of neutron absorption of heavy water, which is a moderator. Before dismantling these facilities, it is necessary to remove tritium from them for not only reducing the amount of tritium released to surrounding environment and the risk of internal exposure by tritium but also ensuring the workability. In first phase of decommissioning (Heavy Water and Other system Decontamination Period), tritium decontamination of the reactor, heavy water system and helium system started in 2008 and completed in 2018. This report shows the results of tritium decontamination of the reactor, heavy water system and helium system.
Aratani, Kenta; Takiya, Hiroaki; Koda, Yuya; Ishiyama, Masahiro; Tezuka, Masashi; Mizui, Hiroyuki
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 5 Pages, 2019/05
The prototype advanced thermal reactor FUGEN is the heavy water-moderated, boiling light water-cooled, pressure tube-type reactor, and has progressing the decommissioning since 2008. The most of facilities such as turbine system have the system structure and the operating conditions similar to those of BWR, although FUGEN has the characteristic structure of reactor core and the heavy water treatment facilities. In Japan, the knowledge and findings from FUGEN decommissioning activities are very important and valuable to perform BWR decommissioning in future, because the decommissioning of FUGEN is research and development as the first decommissioning of real-scale reactor. In the first phase of FUGEN decommissioning activities, the dismantlement project of reactor core cooling system started. By 2017, the low-level contaminated equipment such as the condensers of turbine system and the main-steam pipes of main-steam system was dismantled, and the management data was accumulated. The knowledge and findings from the 10 years of dismantlement experience will be reflected to the future dismantlement of higher contaminated facilities.
Takiya, Hiroaki; Aratani, Kenta; Awatani, Yuto; Ishiyama, Masahiro; Tezuka, Masashi; Mizui, Hiroyuki
Dekomisshoningu Giho, (59), p.2 - 12, 2019/03
FUGEN Decommissioning Engineering Center received the approval of the decommissioning program in 2008, and we have been progressing the decommissioning. The first phase of decommissioning (Heavy Water and Other system Decontamination Period) finished in May 2018, and FUGEN has entered into the second phase of decommissioning (Reactor Periphery Facilities Dismantling Period). This report outlines the results obtained in the first phase of decommissioning of FUGEN.
Takiya, Hiroaki; Ishiyama, Masahiro; Tezuka, Masashi; Kitayama, Naoki
Proceedings of International Conference on Dismantling Challenges; Industrial Reality, Prospects and Feedback Experience (DEM 2018) (Internet), 8 Pages, 2018/10
In FUGEN, we had isolated the reactor core by cutting pipes of the periphery systems (e.g. reactor cooling system, heavy water system, and helium system) between 2015 and 2017, as preparation for dismantling the reactor core and taking some samples from the reactor core structures. There are three issues to be solved at this isolation work; (1) to shorten the working time at high radiation area which is 1-5mSv/h at air and 10mSv/h at contact, (2) to prevent tritium spreading to working area at cutting work because tritium air is existing with 20-30Bq/cm
inside of the heavy water system and helium system, and (3) to minimize the influence of contaminated fume for the accurate radioactivity evaluation of reactor core structure. In this study, considering these problems, we discussed the method for cutting the pipes of heavy water system and helium system at the high radiation area and carried out the pipe cutting in the way.
Kawasaki, Ichio; Ishiyama, Toru; Usui, Masahiro*; Murakami, Toshinori*
Boira Kenkyu, (382), p.26 - 33, 2013/12
There are 4-boiler systems in Nuclear Fuel Cycle Engineering Laboratories. These has been operated in over 16 years. In one of them, the leakage that occurred at generating tube was found at Dec. 2011. The investigation of the leakage was carried out. The leaked generating tube was removed, and the part of leakage was cut off, and the deposit around the leakage was removed to analyze the cause of leakage. The analysis was carried out by SEM,EDX,WDX and XRD. etc. Elements of the deposit accumulated to surface of water drum are mainly O, Fe and S, and then many of component was sulfide. Therefore it seems that generating tube was corroded by sulfide. In future plan, operating method will be review to reduce the deposit, and check item will be selected to find the deposit earlier. This report was described about variously activity for the investigation and a future action.
Yoshimoto, Masahiro; Saha, P. K.; Yamazaki, Yoshio; Kawase, Masato; Saeki, Riuji; Hayashi, Naoki; Yamamoto, Kazami; Hotchi, Hideaki; Ishiyama, Tatsuya; Kinsho, Michikazu; et al.
Journal of Physics; Conference Series, 417, p.012073_1 - 012073_6, 2013/03
Times Cited Count：4 Percentile：75.73(Materials Science, Coatings & Films)The HBC foil are installed in the J-PARC RCS for the charge-exchange H
beam injection. In order to examine the characteristics of the HBC foils, beam studies for the HBC foil were carried out from the viewpoint of foil's life time and the beam survival rate due to foils. According to the compromise between charge-exchange efficiency and foil scattering beam loss, we optimized the foils thickness for user operation. The long-term observation during the user operation as well as the HBC foil endurance test for its life time evaluation was carried out. Even after one year was operation, there was no deterioration of the stripping foil.
Yoshimoto, Masahiro; Yamazaki, Yoshio; Hayashi, Naoki; Yamamoto, Kazami; Saeki, Riuji; Hotchi, Hideaki; Saha, P. K.; Harada, Hiroyuki; Kawase, Masato; Ishiyama, Tatsuya; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3927 - 3929, 2010/05
The (
)ybrid type thick (
)oron-doped (
)arbon (HBC) stripping foils are installed and used for the beam injection at the 3GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex). Up to now, the performance deterioration of the stripping foils can not be seen after the long beam irradiation for the 120kW user operation and 300kW high power beam demonstration at the RCS. In order to examine the characteristic of the HBC foils, various beam studies were carried out. The beam-irradiated spot at the foil was measured by scanning the foil setting position, the charge exchange efficiency was evaluated with various thickness foils, and the effect of the SiC fibers supporting the foil mounting was checked with different mounting foils. Beam study results obtained with using the HBC foils will be presented. In addition, the trends of outgas from the stripping foils and the deformations of the foils during the beam irradiation will be reported.
Kubono, Shigeru*; Teranishi, Takashi*; Notani, Masahiro*; Yamaguchi, Hidetoshi*; Saito, Akito*; He, J. J.*; Wakabayashi, Yasuo*; Fujikawa, Hisashi*; Amadio, G.*; Baba, Hidetada*; et al.
Nuclear Physics A, 758, p.733 - 736, 2005/07
Times Cited Count：1 Percentile：14.45(Physics, Nuclear)With using 
RNB from CRIB, proton inelastic scattering was observed. From this experiment, some resonance parameters have been deduced for the key reaction, 
at the explosive hydrogen burning stage in stars. Proton inelastic scattering of 
are also reported.
Nishiyama, Satoshi*; Uehara, Shinichi*; Yano, Takao*; Saito, Ryuhei*; Uchida, Masahiro; Sawada, Atsushi; Takebe, Atsuji
JNC TY8400 2005-007, 70 Pages, 2005/03
JNC-TY8400-2005-007.pdf:2.24MB
None
Eto, Motokuni; Ishiyama, Shintaro; Fukaya, Kiyoshi; Saito, Tamotsu; Ishihara, Masahiro; Hanawa, Satoshi
JAERI-Research 98-003, 34 Pages, 1998/01
JAERI-Research-98-003.pdf:1.26MB
no abstracts in English
; Nishiyama, Yutaka; Ishihara, Masahiro
Proc. of the 2nd Japan Int. SAMPE Symp. on Advanced Materials for Future Industries,Needs and Seeds, p.1183 - 1190, 1991/00
no abstracts in English
Kitamura, Koichi; Sano, Kazuya; Nakamura, Yasuyuki; Matsushima, Akira; Matsuo, Hidehiko; Ishiyama, Masahiro; Haneda, Takahiro; Tezuka, Masashi
no journal, ,
The decommissioning program of proto-type Advanced Thermal Reactor (ATR) FUGEN has started in 2008 as first decommissioning of the commercial-scale water reactor. It consists of four periods, considering the transportation of spent fuels and the radioactive decrease of highly activated materials. It is expected that the whole program of decommissioning will be completed until 2028.Now, the decommissioning is under the first period, spent fuels and heavy water has been carrying out from FUGEN, and a part of the turbine system with relatively low radioactive contamination has been dismantled. FUGEN has a complicated core structure consisting 224 fuel channels with pressure tubes and calandria tank, etc. and used heavy water as moderator, unlike other light water reactor. So, the dismantling technology of the reactor core and the decontamination technology of tritium in heavy water system, etc. have been studying in order to dismantle them safely. In this presentation, the contents of the decommissioning program and its current status, the studying situation of dismantling technology of reactor core using Abrasive Water Jet (AWJ) which is a candidate of cutting technologies, the examination of tritium decontamination in heavy water system, the study for C-14 penetrated into concrete structure will be presented mainly.
/Si by ion implantationNinakuchi, Yuki*; Saito, Masahiro*; Isshiki, Toshiyuki*; Nishio, Koji*; Nishiyama, Fumitaka*; Yamamoto, Shunya; Sasase, Masato*; Takahiro, Katsumi*
no journal, ,
In the course of Ag implantation into thermally grown SiO films, we found well-ordered Ag nanoparticles in the vicinity of SiO/Si interface. SiO films of 300 nm thick were grown on single crystalline Si(111) substrates. The SiO/Si samples were implanted with 350 keV-Ag ions to a fluence of 1
10
ions/cm
. The Ag-implanted SiO/Si samples were characterized by Rutherford backscattering spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and cross sectional transmission electron microscopy (XTEM). The Ag concentration depth profiles obtained by RBS and XPS were non-Gaussian, indicating that Ag atoms diffused significantly. XTEM revealed that well-arranged Ag nanoparticles of 30 nm and 2 nm in diameter were distributed near the projected range and the SiO/Si interface, respectively.
Matsushima, Akira; Ishiyama, Masahiro; Matsuo, Hidehiko; Sato, Yuji
no journal, ,
no abstracts in English
Ishiyama, Masahiro; Nakamura, Yasuyuki
no journal, ,
We'll attend the 53rd meeting of Technical Advisory Group in America and report the status of turbine facilities dismantlement and the R&D of laser cutting technology.
Takiya, Hiroaki; Matsushima, Akira; Ishiyama, Masahiro; Okuzawa, Kazuhiro
no journal, ,
no abstracts in English
Isomi, Kazuhiko; Matsushima, Akira; Nakayama, Tamotsu; Ishiyama, Masahiro; Nakamura, Yasuyuki
no journal, ,
no abstracts in English
Matsui, Hiroya; Ishiyama, Koji*; Yoshino, Osamu*; Hikima, Ryoichi*; Sanoki, Satoru*; Hayashi, Kunihiko*; Takahashi, Masahiro*; Sato, Masaru*
no journal, ,
This paper is described about the results of collaboration study between Nishimatsu cop. and JAEA to estimate the applicability of high resolution elastic wave velocity measurement for understanding of a groundwater flow. The measurement was carried out in the vicinity of the groundwater recovery test drift in MIU and it continued for about three month from just after starting at the drainage of the test drift. The results suggested that the elastic wave velocity change were measured with groundwater flow due to drainage of the test drift and the high resolution elastic wave velocity measurement can be applicable for understanding of groundwater flow.
