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Nara, Yoshitaka*; Kashiwaya, Koki*; Oketani, Kazuki*; Fujii, Hirokazu*; Zhao, Y.*; Kato, Masaji*; Aoyagi, Kazuhei; Ozaki, Yusuke; Matsui, Hiroya; Kono, Masanori*
Zairyo, 73(3), p.220 - 225, 2024/03
The fractures in the rock are the main pass of groundwater flow and solute transport. The filling of fine-grained particle, such as clay minerals, was confirmed to decrease the permeability of rock by laboratory experiment. This research aimed to verify the occurance of the phoenomena in the fild. The water containing the clay minerals was injected into the rock at the 200m stage of the Mizunami undearground research laboratory. The hydraulic conductivity decreased two order before and after the injection. This result suggested that the decrease of hydraulic conductivity by the filling of fine-grained particle in the fractures occured in the real field.
Morishita, Yuki; Higuchi, Mikio*; Kaneko, Junichi*; Kitagawa, Yuichi*; Akedo, Jun*; Soma, Mitsugu*; Matsui, Hiroaki*
Nuclear Instruments and Methods in Physics Research A, 1057, p.168702_1 - 168702_8, 2023/12
Times Cited Count：0 Percentile：0.02(Instruments & Instrumentation)This paper describes the development of a large-area imaging detector capable of measuring the detailed distribution of alpha particles on hands and feet for use in entry/exit control monitors in decommissioning sites such as the Fukushima Daiichi Nuclear Power Plant. The detector was developed using a commercially available ZnS(Ag) scintillator and an electron multiplying CCD camera. The effectiveness of the detector was evaluated by measuring several types of radiation sources, and the results showed that it was possible to detect the position of alpha particles in a very short time, and contamination levels of up to 11 Bq/cm
could be visualized. As a result of the minimal detectable surface activity concentration evaluations, 2.0 minutes or more is required to achieve 4 Bq/cm, and 25.0 minutes or more is required to achieve 0.4 Bq/cm. The field of view of the detector was also checked, and it was confirmed that the setup had a field of view that could cover most of the hand and the sole of the shoe. This detector is expected to be useful for preventing internal uptake and decontamination.
Kutsukake, Kenichi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi
Proceedings of 20th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1080 - 1084, 2023/11
no abstracts in English
Chiba, Kaori*; Matsui, Takuro*; Chatake, Toshiyuki*; Ohara, Takashi; Tanaka, Ichiro*; Yutani, Katsuhide*; Niimura, Nobuo*
Protein Science, 32(10), p.e4765_1 - e4765_13, 2023/10
Times Cited Count：0 Percentile：0(Biochemistry & Molecular Biology)Kamiya, Junichiro; Nii, Keisuke*; Kabumoto, Hiroshi; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; Matsuda, Makoto; Moriya, Katsuhiro; Ida, Yoshiaki*; et al.
e-Journal of Surface Science and Nanotechnology (Internet), 21(4), p.344 - 349, 2023/05
no abstracts in English
Kabumoto, Hiroshi; Matsuda, Makoto; Nakamura, Masahiko; Ishizaki, Nobuhiro; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Nakagawa, Sohei; Abe, Shinichi
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1109 - 1113, 2023/01
no abstracts in English
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 19th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.601 - 604, 2023/01
no abstracts in English
Morita, Hisashi; Iimura, Koichi; Matsui, Yoshinori; Takemoto, Noriyuki
JAEA-Technology 2022-024, 73 Pages, 2022/11
JAEA-Technology-2022-024.pdf:1.56MB
JMTR was positioned as a decommissioning facility in the facilities mid- and long-term plan (formulated in April 1, 2017) of the Japan Atomic Energy Agency. On September 18, 2019, we applied for approval of the decommissioning plan for the JMTR reactor facility, and received the approval on March 17, 2021. This made it impossible to conduct irradiation tests with nuclear fuel material at the JMTR using facility. Therefore, on August 7, 2020, in order to delete the description about irradiation test and to change accident evaluation, we applied for change of permission to use nuclear fuel material regarding JMTR facility (Facility No. 1) at the Oarai Research and Development Institute (North Area), and received the permission on May 26, 2021. As the accident evaluation, radiation exposure evaluation was performed at the boundary of the surrounding monitoring area assuming a damage accident during transfer work of the irradiated fuel specimen to the hot laboratory. As a result, it was confirmed to satisfy the standards such as the dose notification concerning about external exposure due to atmospheric diffusion, internal exposure due to atmospheric diffusion, external exposure due to direct 
-rays and skyshine -rays. This report summarizes the methods and results of the accident evaluation related to permission change of JMTR using facility.
Iwase, Akihiro*; Fukuda, Kengo*; Saito, Yuichi*; Okamoto, Yoshihiro; Semboshi, Satoshi*; Amekura, Hiroshi*; Matsui, Toshiyuki*
Journal of Applied Physics, 132(16), p.163902_1 - 163902_10, 2022/10
Times Cited Count：0 Percentile：0(Physics, Applied)Amorphous SiO
samples were implanted with 380 keV Fe ions at room temperature. After implantation, some of the samples were irradiated with 16 MeV Au ions. magnetic properties were investigated using a SQUID magnetometer, and the morphology of the Fe-implanted SiO samples was examined using transmission electron microscopy and X-ray absorption spectroscopy (EXAFS and XANES), which showed that the size of Fe nanoparticles was increasing The size of Fe nanoparticles increased with increasing Fe implantation amount; some of the Fe nanoparticles consisted of Fe oxides, and the valence and structure of Fe atoms became closer to that of metallic 
-Fe with increasing Fe injection amount. The magnetization-field curve of the sample implanted with a small amount of Fe was reproduced by Langevin's equation, suggesting that the Fe nanoparticles behave in a superparamagnetic manner. In addition, when a large amount of Fe was implanted, the magnetization-magnetic field curve shows a ferromagnetic state. These magnetic property results are consistent with the X-ray absorption results. Subsequent 16 MeV Au irradiation crushed the Fe nanoparticles, resulting in a decrease in magnetization.
Okada, Yuji; Magome, Hirokatsu; Matsui, Yoshinori
JAEA-Technology 2022-014, 113 Pages, 2022/09
JAEA-Technology-2022-014.pdf:15.79MB
Material irradiation test system had been newly installed in JMTR (Japan Materials Testing Reactor) with taking 5 years which was from 2008 through 2013. The aim of material irradiation test system is to conduct IASCC (Irradiation Assisted Stress Corrosion Cracking) evaluation study. This system is mainly consist of water control unit, which can simulate elevated temperature and pressure of the light water reactor environment in the reactor, and load control unit, which can perform the crack propagation examination under irradiation. This load control unit gives a load to CT (Compact Tension) specimen, and perform the crack propagation examination. The principle of loading to CT specimen is using pressure difference between pressure generated by high temperature and high pressure water by water control unit in capsule and pressure generated by load gas pressure supplied by helium gas cylinder in bellows installed in load control unit. In 2013, the commissioning of material irradiation test system was carried out for adjustment. During this commissioning, the correlation between the differential pressure in load control unit and the load was confirmed by using the test container connected to load control unit with load cell. From the results of commissioning, the problem, which the load change speeds at loading and unloading were different due to different pressure change speeds by the piping resistance performance in the periodic loading test in which load from minimum to maximum repeatedly applied, was confirmed. This report summarizes the problem of load change speed due to the piping resistance performance, which was confirmed in 2013, the improvement and performance test of load control unit for solving the problem described above, which were carried out from 2014 to 2015, and operating procedure.
Motoshima, Takayuki*; Matsui, Hiroya; Kawakubo, Masahiro*; Kobayashi, Masato*; Ichimura, Tetsuhiro*; Sugita, Yutaka
Nihon Genshiryoku Gakkai-Shi ATOMO
, 64(3), p.163 - 167, 2022/03
no abstracts in English
and SrLaCuNbO; Spin-
quasi-square-lattice 
-
Heisenberg antiferromagnetsWatanabe, Masari*; Kurita, Nubuyuki*; Tanaka, Hidekazu*; Ueno, Wataru*; Matsui, Kazuki*; Goto, Takayuki*; Hagihara, Masato
Physical Review B, 105(5), p.054414_1 - 054414_12, 2022/02
Times Cited Count：4 Percentile：59.24(Materials Science, Multidisciplinary)Osawa, Hideaki; Matsui, Hideki
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 28(2), p.18 - 25, 2021/12
The Japan Atomic Energy Agency had offered visitor's tour to the underground and surface facilities of the Mizunami Underground Research Laboratory (URL) at the Tono Geoscience Center in order to promote the understanding of the R&D of geological disposal technology and geological disposal for the public. We analyzed questionnaires distributed after visiting these facilities from FY2010 to FY2019, except for FY2016, in the hopes of using risk communication for geological disposal. Results suggest that visiting these facilities is a valuable experience to understand geological disposal because some people, knew even just a little bit about it, have positively evaluated appropriateness of geological disposal by a tour of the Mizunami URL. While some people who have negatively evaluated safety of geological disposal are highly interested in issues of nuclear power and site selection, some people who have positively evaluated safety of geological disposal are highly interested in public understanding of geological disposal. Furthermore, both these groups believe that long-term safety is a technical issue.
Otsuka, Yusuke*; Kanazawa, Naoya*; Hirayama, Motoaki*; Matsui, Akira*; Nomoto, Takuya*; Arita, Ryotaro*; Nakajima, Taro*; Hanashima, Takayasu*; Ukleev, V.*; Aoki, Hiroyuki; et al.
Science Advances (Internet), 7(47), p.eabj0498_1 - eabj0498_9, 2021/11
Times Cited Count：7 Percentile：40.96(Multidisciplinary Sciences)Matsuda, Makoto; Tayama, Hidekazu; Ishizaki, Nobuhiro; Kabumoto, Hiroshi; Nakamura, Masahiko; Kutsukake, Kenichi; Otokawa, Yoshinori; Asozu, Takuhiro; Matsui, Yutaka; Abe, Shinichi
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.394 - 398, 2021/10
no abstracts in English
Nii, Keisuke*; Ida, Yoshiaki*; Ueda, Hideki*; Yamaguchi, Takanori*; Kabumoto, Hiroshi; Kamiya, Junichiro; Kondo, Yasuhiro; Tamura, Jun; Harada, Hiroyuki; Matsui, Yutaka; et al.
Proceedings of 18th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.334 - 337, 2021/10
no abstracts in English
Hirouchi, Jun; Takahara, Shogo; Komagamine, Hiroshi*; Kato, Nobuyuki*; Matsui, Yasuto*; Yoneda, Minoru*
Journal of Radiological Protection, 41(3), p.S139 - S149, 2021/09
Times Cited Count：2 Percentile：31.78(Environmental Sciences)Sheltering is one of the countermeasures for protection against radiation exposures in nuclear accidents. The effectiveness of sheltering is often expressed by the reduction factor, that is the ratio of the indoor to the outdoor cumulative radioactivity concentrations or doses. The indoor concentration is mainly controlled by the air exchange rate, penetration factor, and indoor deposition rate. The penetration factor and indoor deposition rate depend on the surface and opening materials. We investigated experimentally these parameters of I and particles. The experiment was performed in two apartment houses, three single-family houses, and chambers. The obtained penetration factor ranged 0.3 
1 for particles of 0.3 1 
m and 0.15 0.7 for I depending on the air exchange rate. The indoor deposition rate for a house room ranged 0.007 0.2 h
for particles of 0.31 m and 0.21.5 h for I depending on floor materials.
Magome, Hirokatsu; Iimura, Koichi; Matsui, Yoshinori
JAEA-Testing 2020-008, 52 Pages, 2021/02
JAEA-Testing-2020-008.pdf:5.46MB
As to the removal of the hydraulic rabbit No.1 irradiation facility related to the decommissioning of JMTR, points to be noted for considering a removal plan and maintenance methods after the removal were studied based on the past experiences of removing the hydraulic rabbit No.2 irradiation facility. As results, it became clear that it was necessary to (1) add a shutoff valve and a closing flange to piping for preventing cooling water leakage, (2) prepare a drawing jig for inner tube, and (3) shorten the remaining piping to withstand earthquakes. In addition, regarding the management of equipment to be maintained after removal, the necessary management items for the removal methods of the three patterns of ground equipments were listed.
Magome, Hirokatsu; Iimura, Koichi; Matsui, Yoshinori
JAEA-Technology 2020-022, 32 Pages, 2021/02
JAEA-Technology-2020-022.pdf:4.04MB
Among the canal underwater equipment of HR-1, seismic evaluations of the canal side wall parts and the canal bottom surface parts were carried out for the insertion device, take-out device and decay tank. As a result, it was confirmed that the equipments have sufficient seismic resistances because the maximum stress of the canal side wall joint, the bolt portion of the canal bottom joint, and the fillet weld are within the allowable stress.
Okano, Aoi*; Kimoto, Kazushi*; Matsui, Hiroya
Dai-15-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), p.633 - 636, 2021/01
This study evaluates the acoustic anisotropy of granite using surface waves. It is well-known that granite shows acoustic anisotropy due to preferentially oriented microcracks. Therefore it may be possible to gain information on the microcracks from the measurement of the acoustic anisotropy. In the conventional rock core elastic wave test, acoustic anisotropy has been evaluated by the ultrasonic transmission test. However, it is difficult to apply this method to field measurement and irregularly-shaped specimens. Therefore, in this study, we attempted to evaluate the acoustic anisotropy of granite using surface waves. By this method, the acoustic anisotropy was evaluated based on the changes in the surface wave amplitude, velocity, and frequency when the transmission direction was varied stepwise at a constant angle. As a result, the proposed surface wave technique evaluated acoustic anisotropy successfully. Furthermore, it was found that the acoustic anisotropy emerges because the microcracks change the apparent rigidity of the granite specimen.
