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Iwamori, Akiyuki*; Ogita, Yasuhiro; Shimada, Koji; Tateishi, Ryo*; Takagi, Hideo*; Ota, Toru*; Cho, T.*; Kudo, Shunsuke*; Nojiri, Keisuke*; Shigemitsu, Yasumune*; et al.
Engineering Geology, 344, p.107821_1 - 107821_20, 2025/01
Times Cited Count：0 Percentile：0.00(Engineering, Geological)Clarification of the physicochemical characterization of brittle fault rocks is important not only for understanding the history of the fault activity and deformation mechanisms, but also for assessing the siting conditions of important facilities such as nuclear power plants, radioactive waste disposal sites, and oil storage bases. Here, we apply the chemical weathering index (W values) to the brittle fault rocks of the Shiraki-Nyu fault (granite), the Tsuruga fault (geological boundary between granite and greenstone), and the Yamada fault (adamellite), which are active faults in the peripheral area of Wakasa Bay, and their respective protoliths (hard rocks), and investigate the physicochemical characteristics of the youngest active domain of brittle fault rocks based on the relationship between computed tomography data (CT numbers) and alteration intensity (AI values). The W values of the fault rocks are mainly affected by changes in Na
O and CaO, corresponding to the elution or deposition of plagioclase and calsite for granite, clinopyroxene and hornblende for greenstone, and plagioclase for adamellite. The W values mainly indicate the effects of hydrothermal alteration up to 50 
60 percent and of weathering at over 60 percent. On the other hand, the CT values of the fault rocks are lowest in the fault gouge corresponding to the latest active zone, which was identified as the lowest density zone. In addition, fresh plagioclase fragments are present in each fault gouge of the latest active zone of the active faults in this study. The application of W values to brittle fault rocks is an effective method for understanding the trends of mineralogical variations associated with hydrothermal alteration and weathering in fault rocks, and it is highly possible to improve the accuracy of identifying the youngest active domain in major fault zones through joint analyses of CT numbers.
Yamane, Ikumi; Takahashi, Nobuo; Sawayama, Kengo; Nishiwaki, Hiroki; Matsumoto, Takashi; Ogawa, Jumpei; Nomura, Mitsuo; Arima, Tatsumi*
JAEA-Technology 2021-038, 18 Pages, 2022/02
JAEA-Technology-2021-038.pdf:1.61MB
We have dismantled uranium enrichment facilities in Ningyo-toge Environmental Engineering Center since their operation finished in 2001, and the total amount of metallic wastes is estimated to be about 130 thousand tons. Eighty percent of them can be disposed as nonradioactive waste (NR), but there are some steel parts possibly uranium-contaminated. We need removing painted surface of such steels and radiologically surveying to dispose them as NRs. Though painted surfaces have been conventionally removed through hand working with grinders, this manual work requires installation of green house, protective clothing, and full-face mask, in order to prevent dispersion and inhalation of airborne dusts. We desire further developments of surface cleaning techniques to reduce time, cost, workload, and secondary waste generation caused by excessive grinding. Therefore, in this study, we focused on the laser cleaning technology used for the separation and removal of paint films at construction sites. In order to improve the coating separation and removal technology for NR objects, we evaluated the coating separation and removal performance of NR steel surface by laser cleaning system, observed the coating scattering behavior by high-speed camera and investigated the coating recovery method, evaluated the laser separation and removal performance of steel surface powder, and thermodynamically evaluated the uranium compounds on steel surface. We additionally evaluated the feasibility of laser cleaning techniques in our works basing on these results, and discussed future work plans for further developments of laser cleaning techniques.
Kumagai, Yuta; Nagaishi, Ryuji; Kimura, Atsushi*; Taguchi, Mitsumasa*; Nishihara, Kenji; Yamagishi, Isao; Ogawa, Toru
Insights Concerning the Fukushima Daiichi Nuclear Accident, Vol.4; Endeavors by Scientists, p.37 - 45, 2021/10
Zeolite adsorbents are to be used for decontamination of radioactive water in Fukushima Dai-ichi Nuclear Power Station. Evaluation of hydrogen production by water radiolysis during decontamination is important for safe operation. Thus hydrogen production from the mixture of zeolite adsorbents and seawater was studied because seawater was urgently used as a coolant for the fuels. The hydrogen yield from the mixture decreased at a high weight fraction of zeolites. However, the measured yield was higher than the yield expected from the direct radiolysis of seawater in the mixture, which would decrease proportional to the weight fraction of seawater. The result suggests that the radiation energy deposited to zeolites was involved in the hydrogen formation. From the results, the hydrogen production rate was evaluated to be 3.6 mL/h per ton of radioactive water before decontamination. After the process, it was evaluated to be 1.5 L/h per ton of waste adsorbents due to the high dose rate.
(001) surface using supersonic seeded oxygen molecular beamKatsube, Daiki*; Ono, Shinya*; Takayanagi, Shuhei*; Ojima, Shoki*; Maeda, Motoyasu*; Origuchi, Naoki*; Ogawa, Arata*; Ikeda, Natsuki*; Aoyagi, Yoshihide*; Kabutoya, Yuito*; et al.
Langmuir, 37(42), p.12313 - 12317, 2021/10
Times Cited Count：3 Percentile：14.81(Chemistry, Multidisciplinary)We investigated the oxidation of oxygen vacancies at the surface of anatase TiO(001) using supersonic seeded molecular beam (SSMB) of oxygen. The oxygen vacancies at the top-surface and sub-surface could be eliminated by the supply of oxygen using an SSMB. These results indicate that the interstitial vacancies can be mostly assigned to oxygen vacancies, which can be effectively eliminated by using an oxygen SSMB. Oxygen vacancies are present on the surface of anatase TiO(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the as-grown condition, could also be effectively eliminated using the oxygen SSMB.
Mukai, Yasunobu; Ogawa, Tsuyoshi; Nakamura, Hironobu; Kurita, Tsutomu; Sekine, Megumi; Rodriguez, D.; Takamine, Jun; Koizumi, Mitsuo; Seya, Michio
Proceedings of INMM 57th Annual Meeting (Internet), 7 Pages, 2016/07
The development of Delayed Gamma-ray Spectroscopy (DGS) for analyzing the composition ratio of fissile nuclides (
Pu, 
Pu, 
U) focused on the Delayed Gamma-ray having energy over 3 MeV has been performed for the development of active neutron non-destructive assay techniques. In PCDF, measurement tests of Delayed Gamma-ray using Pu solution and MOX powder samples to prove the DGS technique is planned to be performed in following 4 stages. (1) Measurements for Delayed Gamma-ray originated from spontaneous fission nuclide (Passive), (2) Measurements for the Delayed Gamma-ray with fast neutron (Active), (3) DGSI (DGS combined with self-interrogation) measurements (Passive), (4) Measurements for the Delayed Gamma-ray with thermal neutron (Active) In this paper, the plan of measurement tests for nuclear material samples with use of DGS is presented.
Tomizawa, Hiromitsu*; Sato, Takahiro*; Ogawa, Kanade*; Togawa, Kazuaki*; Tanaka, Takatsugu*; Hara, Toru*; Yabashi, Makina*; Tanaka, Hitoshi*; Ishikawa, Tetsuya*; Togashi, Tadashi*; et al.
High Power Laser Science and Engineering, 3, p.e14_1 - e14_10, 2015/04
Times Cited Count：8 Percentile：40.56(Optics)no abstracts in English
-ray for improvement neutron emission profile measurementUchida, Yuki*; Takada, Eiji*; Fujisaki, Akihiro*; Isobe, Mitsutaka*; Ogawa, Kunihiro*; Shinohara, Koji; Tomita, Hideki*; Kawarabayashi, Jun*; Iguchi, Tetsuo*
Review of Scientific Instruments, 85(11), p.11E118_1 - 11E118_4, 2014/11
Times Cited Count：10 Percentile：37.94(Instruments & Instrumentation)Kawamura, Masato*; Chishiro, Etsuji; Hori, Toshihiko; Shinozaki, Shinichi; Sato, Fumiaki; Fukui, Yuji*; Futatsukawa, Kenta*; Yamazaki, Masayoshi*; Sagawa, Ryu*; Miyajima, Noriyuki*; et al.
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.605 - 607, 2014/06
This report describes the present status of the klystron power supply systems for the J-PARC linac. The systems for the 181 MeV linac were operated from September to May. A few breakdowns were occurred, and are described in this report. The new systems for the upgrade of the linac from 181MeV to 400 MeV have been installed until now, and the 3 HVDCPSs and the 3 anode modulators of the new systems have been operated. All the systems for 400 MeV linac will be operated in this autumn.
Yano, Yasuhide; Otsuka, Satoshi; Yamashita, Shinichiro; Ogawa, Ryuichiro; Sekine, Manabu; Endo, Toshiaki; Yamagata, Ichiro; Sekio, Yoshihiro; Tanno, Takashi; Uwaba, Tomoyuki; et al.
JAEA-Research 2013-030, 57 Pages, 2013/11
JAEA-Research-2013-030.pdf:48.2MB
It is necessary to develop the fast reactor core materials, which can achieve high-burnup operation improving safety and economical performance. Ferritic steels are expected to be good candidate core materials to achieve this objective because of their excellent void swelling resistance. Therefore, oxide dispersion strengthened (ODS) ferritic steel and 11Cr-ferritic/martensitic steel (PNC-FMS) have been respectively developed for cladding and wrapper tube materials in Japan Atomic Energy Agency. In this study, the effects of fast neutron irradiation on mechanical properties and microstructure of 9Cr-and 12Cr-ODS steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the CMIR-6 at temperatures between 420 and 835
C to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures.
Kawamura, Masato*; Chishiro, Etsuji; Hori, Toshihiko; Shinozaki, Shinichi; Sato, Fumiaki; Fukui, Yuji*; Futatsukawa, Kenta*; Yamazaki, Masayoshi*; Sagawa, Ryu*; Yukitake, Mitsuteru*; et al.
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1243 - 1247, 2013/08
no abstracts in English
Ogawa, Kanade*; Sato, Takahiro*; Matsubara, Shinichi*; Okayasu, Yuichi*; Togashi, Tadashi*; Watanabe, Takahiro*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; et al.
Proceedings of 10th Conference on Lasers and Electro-Optics Pacific Rim and 18th OptoElectronics and Communications Conference and Photonics in Switching 2013 (CLEO-PR & OECC/PS 2013) (USB Flash Drive), 2 Pages, 2013/06
no abstracts in English
Togashi, Tadashi*; Takahashi, Eiji*; Midorikawa, Katsumi*; Aoyama, Makoto; Yamakawa, Koichi; Sato, Takahiro*; Iwasaki, Atsushi*; Owada, Shigeki*; Yamanouchi, Kaoru*; Hara, Toru*; et al.
Proceedings of Ultrafast Optics IX (CD-ROM), 2 Pages, 2013/03
We have demonstrated free-electron laser radiation seeded by high-order harmonics in the extreme-ultraviolet region. Strong enhancement of the radiation intensity by a factor of 104 was observed with timing control of an electro-optical sampling technique.
Okayasu, Yuichi*; Tomizawa, Hiromitsu*; Matsubara, Shinichi*; Sato, Takahiro*; Ogawa, Kanade*; Togashi, Tadashi*; Takahashi, Eiji*; Minamide, Hiroaki*; Matsukawa, Ken*; Aoyama, Makoto; et al.
Proceedings of 1st International Beam Instrumentation Conference (IBIC 2012) (Internet), 5 Pages, 2012/10
no abstracts in English
Iguchi, Masahide; Chida, Yutaka; Takano, Katsutoshi; Kawano, Katsumi; Saito, Toru; Nakajima, Hideo; Koizumi, Norikiyo; Minemura, Toshiyuki*; Ogata, Hiroshige*; Ogawa, Tsuyoshi*; et al.
IEEE Transactions on Applied Superconductivity, 22(3), p.4203305_1 - 4203305_5, 2012/06
Times Cited Count：10 Percentile：49.10(Engineering, Electrical & Electronic)Japan Atomic Energy Agency (JAEA) has responsibility to procure 19 structures for ITER toroidal field (TF) coils as in-kind components. JAEA plans to use materials specified in the material section of "Codes for Fusion Facilities; Rules on Superconducting Magnet Structure (2008)" issued by the Japan Society of Mechanical Engineers (JSME) in 2008. Large forged products were produced and their mechanical properties at 4K were evaluated. In addition, the following activities have been performed; (1) to optimize the design of each weld type identified in the manufacturing sequence, (2) to qualify typical welding procedure including repair, (3) to establish welding techniques other than narrow gap TIG welding with FMYJJ1, (4) to demonstrate the manufacturing procedures through manufacture of 1-m mockups and full-scale segments of TFC structure. This paper describes the results of material qualification and industrialization activities of manufacturing processes of ITER TFC structure.
Yano, Yasuhide; Ogawa, Ryuichiro; Yamashita, Shinichiro; Otsuka, Satoshi; Kaito, Takeji; Akasaka, Naoaki; Inoue, Masaki; Yoshitake, Tsunemitsu; Tanaka, Kenya
Journal of Nuclear Materials, 419(1-3), p.305 - 309, 2011/12
Times Cited Count：23 Percentile：82.08(Materials Science, Multidisciplinary)The effects of fast neutron irradiation on ring tensile properties of oxide dispersion strengthened (ODS) steel claddings for fast reactor were investigated. Specimens were irradiated in the experimental fast reactor Joyo using the material irradiation rig at temperatures between 693 and 1108 K to fast neutron doses ranging from 16 to 33 dpa. The post-irradiation ring tensile tests were carried out at irradiation temperatures. The experimental results showed that there was no significant change in tensile strengths after neutron irradiation below 923 K, but the tensile strengths at neutron irradiation above 1023 K up to 33 dpa were decreased by about 20%. On the other hand, uniform elongation after irradiation was more than 2% at all irradiation conditions. The ring tensile properties of these ODS claddings remained excellent within these irradiation conditions compared with conventional 11Cr ferritic/martensitic steel (PNC-FMS) claddings.
Kumagai, Yuta; Nagaishi, Ryuji; Kimura, Atsushi; Taguchi, Mitsumasa; Nishihara, Kenji; Yamagishi, Isao; Ogawa, Toru
Nihon Genshiryoku Gakkai Wabun Rombunshi, 10(4), p.235 - 239, 2011/12
Zeolite adsorbents are to be used for decontamination of radioactive water in Fukushima Dai-ichi Nuclear Power Station. Evaluation of hydrogen production by water radiolysis during decontamination is important for safe operation. Thus hydrogen production from the mixture of zeolite adsorbents and seawater was studied because seawater was urgently used as a coolant for the fuels. The hydrogen yield from the mixture decreased at a high weight fraction of zeolites. However, the measured yield was higher than the yield expected from the direct radiolysis of seawater in the mixture, which would decrease proportional to the weight fraction of seawater. The result suggests that the radiation energy deposited to zeolite is involved in the hydrogen formation. From the results, the hydrogen production rate was evaluated to be 3.6 mL/h per ton of radioactive water before decontamination. After the process, it was evaluated to be 1.5 L/h per ton of waste adsorbents due to the high dose rate.
Hosokawa, Jinsaku; Iimura, Koichi; Ogawa, Mitsuhiro; Tomita, Kenji; Yamaura, Takayuki
JAEA-Technology 2010-018, 269 Pages, 2010/08
JAEA-Technology-2010-018.pdf:5.75MB
At Oarai Research and Development Center, Japan Atomic Energy Agency (JAEA) advances the plan of refurbishing Japan Materials Testing Reactor (JMTR) to start the operation in fiscal 2011. Fuel Transient Test Facility is scheduled to be set up as neutron irradiation test equipment of the light-water reactor fuel that uses JMTR after it operates again. The abnormal transition examination device is the irradiation facilities where the output sudden rise examination that makes the light-water reactor fuel an irradiation sample is done to use it to develop the safety evaluation technology and the damage influence evaluation technology of the light-water reactor fuel that reaches high burn-up. In this report, as for the system design, it is a summary to JMTR among detailed designs of the abnormal transition examination device of the installation schedule.
Ogawa, Mitsuhiro; Iimura, Koichi; Hosokawa, Jinsaku; Kanno, Masaru
JAEA-Technology 2010-019, 178 Pages, 2010/07
JAEA-Technology-2010-019.pdf:20.16MB
JMTR is making preparations of the irradiation examinations towards the re-operation from the 2011 fiscal year now. Design examination of the high-duty irradiation loop is in one of these irradiation examinations of the irradiation plan. The examination is the plan to carry out the irradiation examination of the light water reactor fuel (uranium fuel and mixed oxide fuel) which reached the high burnup, under the irradiation environment nearer to the light water reactor plant. In the 2009 fiscal year, we carried out (1) System design and (2) Earthquake-proof calculation of in-pile tube of the high-duty irradiation loop. And, for the fuel action between covering pipe and pellets of fuel rod which reached the high burnup, we carried out (3) System design of the lift-off test facility. Moreover, we carried out (4) Examination about detection system of fuel breakage when a fuel sample is damaged, and (5) Examination about system composition of effluent treatment system.
Kikuchi, Masahiro; Ogawa, Hideyuki*; Morishita, Norio; Ukai, Mitsuko*; Kobayashi, Yasuhiko; Shimoyama, Yuhei*
Shokuhin Shosha, 44(1-2), p.9 - 13, 2009/09
no abstracts in English
Iimura, Koichi; Yamaura, Takayuki; Ogawa, Mitsuhiro
JAEA-Technology 2009-033, 45 Pages, 2009/07
JAEA-Technology-2009-033.pdf:5.01MB
At Oarai Research and development center, Japan Atomic Energy Agency (JAEA), the plan of repairing and refurbishing Japan Materials Testing Reactor (JMTR) has progressed in order to restart JMTR operation in the fiscal 2011. By using Oarari Shroud Facility and fuel irradiation facility with the He-3 gas control system for power lamping test using boiling water capsules. By using saturated temperature capsules and the water environment control system, the material irradiation tests under the water chemistry condition of LWL will be carried out to clarify the mechanism of IASCC. The detailed design for renewal or remodeling was carried out based on the new design condition in order to be correspondent to the irradiation test plan after restart JMTR operation. Stress calculation and evaluation were carried out by fem piping analysis code SAP and structure analysis code ABAQUS. It was proven by the analysis that these facilities maintain the structural integrity under earthquake condition.
