Shoji, Eita*; Isogai, Shosei*; Suzuki, Rikuto*; Kubo, Masaki*; Tsukada, Takao*; Kai, Tetsuya; Shinohara, Takenao; Matsumoto, Yoshihiro*; Fukuyama, Hiroyuki*
Scripta Materialia, 175, p.29 - 32, 2020/01
Manabe, Kentaro; Matsumoto, Masaki*
Journal of Nuclear Science and Technology, 56(1), p.78 - 86, 2019/01
If an insoluble cesium-bearing particle is incorporated into the human body, the radioactivity will move as a single particle. In this case, it is impossible to estimate the number of disintegrations by considering the average behavior of countless nuclei. Then, a method was developed to simulate the behavior of the particle stochastically; and a biokinetic model was constructed to consider the characteristics of insoluble particles. Combination of the method and the model enables to estimate the number of disintegrations, and consequently the internal doses considering the stochastic behavior of the single cesium particle. We evaluated a probability density function of committed equivalent and effective doses and its 99th percentile value and arithmetic mean by repeating the above described procedure, and compared them to the reference values based on the existing models. As a result, the 99th percentile value of committed effective doses was 70 times the reference value when the number of incorporated particles was one, and consequently the dose level was quite low. When the exposure level is 1 mSv in committed effective dose, the uncertainty originating in the insolubility of cesium particles was negligibly small.
Ishikawa, Tetsuo*; Matsumoto, Masaki*; Sato, Tatsuhiko; Yamaguchi, Ichiro*; Kai, Michiaki*
Journal of Radiological Protection, 38(4), p.1253 - 1268, 2018/12
The current knowledge on internal dose estimation and its health effect were reviewed in this paper. The goals were to discuss the uncertainty of current dose coefficients, to compare the effects of external and internal exposures, and to review recent epidemiological studies. Radionuclides focused on in this study were caesium-137 (Cs), caesium-134 (Cs), and iodine-131 (I), which primarily contributed to internal effective thyroid doses after the Fukushima Dai-ichi Nuclear Power Station accident. Current knowledge suggests that the risk of internal exposure could be generally the same as or less than that of external exposure, when they are compared at the same effective dose.
Cheung, Y. W.*; Hu, Y. J.*; Goh, S. K.*; Kaneko, Koji; Tsutsui, Satoshi; Logg, P. W.*; Grosche, F. M.*; Kanagawa, Hibiki*; Tanioku, Yasuaki*; Imai, Masaki*; et al.
Journal of Physics; Conference Series, 807(3), p.032002_1 - 032002_4, 2017/04
Mikami, Satoshi; Matsuda, Norihiro; Ando, Masaki; Kinase, Sakae; Kitano, Mitsuaki; Kawase, Keiichi; Matsumoto, Shinichiro; Yamamoto, Hideaki; Saito, Kimiaki
Radioisotopes, 64(9), p.589 - 607, 2015/09
This article presents the features of regional distributions and temporal changes in air dose rate and radionuclide deposition densities in Fukushima on the basis of analyses on large-scale environmental monitoring results using diverse methods. The continuity of decontamination effects is discussed according to repeated monitoring data after the decontamination model project. Further, some examples are shown on the projection of air dose rates together with the ecological half lives for different land uses.
Matsumoto, Koji*; Sagara, Hiroshi*; Han, C. Y.*; Onishi, Takashi; Saito, Masaki*; Yamauchi, Ippei*
Transactions of the American Nuclear Society, 107(1), p.1018 - 1019, 2012/11
Protected plutonium production (P) with a high proliferation-resistance was proposed by increasing the Pu ratio in the total plutonium through minor actinides (MAs) doping into the fresh blanket fuel. Moderator effect on P was evaluated. As a result, the transmutation ratio is larger with the heterogeneous moderator than with the homogeneous one, and the isotopic ratio of Pu was increased.
Yabuuchi, Atsushi; Maekawa, Masaki; Kawasuso, Atsuo; Entani, Shiro; Matsumoto, Yoshihiro; Sakai, Seiji; Yamamoto, Shunya
JAEA-Review 2010-065, JAEA Takasaki Annual Report 2009, P. 131, 2011/01
Ion implantation technique is expected to be useful in fabrication of diluted magnetic semiconductors (DMS) that require high concentration magnetic atom doping without a secondary phase formation. However, ion implantation surely introduces irradiation-induced vacancies into crystals. Recent calculation studies have suggested a presence of vacancies affect the magnetic properties in DMS. In this study, magnetic ions were implanted into compound semiconductor crystals by using ion implantation. N-type ZnO(0001) crystals were implanted with 380 keV maximum energy Cr ions to a dose of 110 ions/cm. After ion implantation, isochronal annealing in steps of 30 min/100 C was performed. From the measurement results, irradiation-induced vacancies were annealed out at 900 C. From XRD measurements after annealing at 1100 C, no secondary phase peaks were observed. However, from SQUID measurement, a clear magnetic hysteresis was not observed.
Toyama, Takeshi*; Arakawa, Dai*; Hiramatsu, Shigenori*; Igarashi, Susumu*; Lee, S.*; Matsumoto, Hiroshi*; Odagiri, Junichi*; Tejima, Masaki*; Tobiyama, Makoto*; Hashimoto, Yoshinori*; et al.
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.981 - 983, 2010/05
Experiences of operating BPM's during beam commissioning at the J-PARC MR are reported. The subjects are: (1) bug report, statistics and especially the effect of a beam duct step, (2) position resolution estimation (30 micrometers with 1 sec averaging), (3) beam based alignment.
Kawasaki, Kenji*; Ando, Masaki; Okajima, Shigeaki; Fukushima, Masahiro; Nakano, Makoto*; Matsumoto, Hideki*
JAEA-Research 2006-008, 40 Pages, 2006/03
Analysis was performed to evaluate prediction accuracy of a neutronics code system for thermal reactor; the SRAC system with the use of the latest nuclear data library JENDL-3.3 for the U Doppler effect measured in the uranium fueled (FCA-XXI-1D2) and MOX fueled (XXII-1 series) cores. The results of the analysis with the diffusion theory showed overestimation by up to +11%. In relatively soft neutron spectra, however, the calculated values agreed with the experimental ones within the experimental errors.
Okada, Takashi; Asazuma, Shinichiro; Kashiro, Kashio; Matsumoto, Masaki
CD-ROM, WM-5214, p.8, 8 Pages, 2005/00
The dismantling activities, which consist of removal of the glove panel, dismantling of the interior equipment and dismantling of the GB body and made up about 45% of the dismantling of the GB in GBDF, could be performed by remote control.
Tobita, Noriyuki; Okada, Takashi; Kashiro, Kashio; Matsumoto, Masaki; Watahiki, Masatoshi; Nakata, Keiji*; Gonnokami, Kiyomi*
JNC TN8430 2004-001, 125 Pages, 2004/12
An event that a pre-filter burned on fire took place in the glove box dismantlement facility of Plutonium Production Facility, on April 21, 2003. The direct cause of this event was considered to be sparks generated by an abrasive wheel cutter, some of which reached the pre-filter and eventually burned the pre-filter. Further investigation revealed that there exist other deficiencies those of which formed indirect causes of the event, such as the wheel cutter was used without protective cover and adequate shield against sparks was not installed during the operation. To prevent similar event in the future, following corrective actions were introduced. Wheel cutter will not be used without protective cover; Incombustible pre-filter will be used; Shield will be place at the front of the pre-filter. We have conducted series of experimental tests in order to evaluate and confirm the validity of these corrective actions as well as determine the cause of the fire. This report present the results of these tests.
Kamaya, Eiki*; Matsumoto, Fukashi*; Kondo, Yasuhiro*; Chujo, Yoshiki*; Katagiri, Masaki
Nuclear Instruments and Methods in Physics Research A, 529(1-3), p.329 - 331, 2004/08
no abstracts in English
Ozawa, Masaki; Uchiyama, Gunzo; Matsumoto, Shiro*
Nihon Genshiryoku Gakkai-Shi, 46(2), p.144 - 146, 2004/02
Asazuma, Shinichiro; Okada, Takashi; Kashiro, Kashio; Matsumoto, Masaki; Nakata, Keiji*; Gonnokami, Kiyomi*; Toda, Rikiya*
JNC TN8430 2003-011, 56 Pages, 2004/01
The glove-box dismantling facility in the Plutonium Fuel Production Facility is developed to dismantle after-service glove-boxes with remote-controlled devices such as an arm-type manipulator. An abrasive wheel cutter, which is used to size reduce the gloveboxes, generates sparks during operation. This dispersing spark was a problem from the fire prevention point of view. A suitable spark control measures for this operation were required. We developed panels to minimize spark dispersion, shields to prevent the income of sparks to the pre-filter, and incombustible pre-filters. The equipment was tested and effectiveness was confirmed. This report provides the results of these tests.
Matsumoto, Shiro*; Uchiyama, Gunzo; Ozawa, Masaki*; Kobayashi, Y.*; Shirato, K.*
Radiochemistry, 45(3), p.219 - 224, 2003/05
no abstracts in English
Kashiro, Kashio; Matsumoto, Masaki
JNC TN8440 2000-015, 25 Pages, 2000/05
All of the glove boxes in Plutonium Fuel Fabrication facilities are operated after confirming their condition by conducting negative pressure maintenance test and air-tighten test. Although we check the negative pressure maintenance condition before operating glove boxes in a daily basis, we have not been conducted the air-tighten test. Hence, we have conducted air-tighten test using the glove box that will be dismantled in the near future. In order to compare the present data to the criteria of licensing and to the measurement data for new glove box, the test was conducted by leak tightness vessel which is used the competent authority's test for newly constructed equipments. We also have confirmed the leakage condition in case failure of keeping negative pressure. The main results are as follows. (1)No leakage was detected after leaving the glove box 21 days in case failure of keeping negative pressure condition. (2)The measurement result of the air-tighten test was 0.025 vol%/h, and it was confirmed that this result is within the range of licensing criteria (-0.040.06 vol%/h). (3)The measurement result was also within the error of leak tightness vessel, and it was confirmed that the air-tighten condition was in force within this past 10 years after installing this glove box (the corresponding value for used the competent authority test for newly constructed equipments was 0.019 vol%/h).
Sugimoto, Masaki; Kudo, Hisaaki; Sasuga, Tsuneo; Seguchi, Tadao; Hama, Yoshimasa*; Hamanaka, Kenichi*; Matsumoto, Hideya*
JAERI-Conf 97-003, p.269 - 272, 1997/03
no abstracts in English
Hama, Yoshimasa*; *; Matsumoto, Hideya*; *; Kudo, Hisaaki; Sugimoto, Masaki; Seguchi, Tadao
Radiation Physics and Chemistry, 48(5), p.549 - 554, 1996/00
no abstracts in English
Proceedings of International Conference on Fast Reactors and Related Fuel Cycles (FR '91), 0 Pages, 1991/10
Kato, Junya; Miyauchi, Atsushi; Aoshima, Atsushi; Shiotsuki, Masao; Yamashita, Teruo; Nakajima, Masayoshi; Morikawa, Yo; Miura, Akihiko; Fukui, Toshiki*; Yamasaki, Akito*; et al.
no journal, ,
no abstracts in English