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Takasaki, Koji; Yasumune, Takashi; Yamaguchi, Yukako; Hashimoto, Makoto; Maeda, Koji; Kato, Masato
Journal of Nuclear Science and Technology, 60(11), p.1437 - 1446, 2023/11
Times Cited Count:0 Percentile:0.01(Nuclear Science & Technology)The aerodynamic radioactive median diameter (AMAD) is necessary information to assess the internal exposure. On June 6, 2017, at a plutonium handling facility in Oarai site of Japan Atomic Energy Agency (JAEA), during the inspection work of a storage container that contains nuclear fuel materials, accidental contamination occurred and five workers inhaled radioactive materials including plutonium. Some smear papers and an air sampling filter were measured with the imaging plate, and we conservatively estimated minimum AMADs for two cases, plutonium nitrate and plutonium dioxide. As a result of AMAD estimation, even excluding a giant particle of a smear sample, the minimum AMADs of plutonium nitrate from smear papers were 4.3 - 11.3 m and those of plutonium dioxide were 5.6 - 14.1 m. Also, the minimum AMAD of plutonium nitrate from an air sampling filter was 3.0 m and that of plutonium dioxide was 3.9 m.
Arthur, R.*; Sasamoto, Hiroshi; Alt-Epping, P.*; Tachi, Yukio
Applied Geochemistry, 155, p.105707_1 - 105707_8, 2023/08
Times Cited Count:1 Percentile:51.18(Geochemistry & Geophysics)The experience gained in modeling the evolution, from past to present, of natural tracer profiles in geologic media can help support safety assessment of disposal concepts for radioactive wastes in deep geologic repository. Solute-transport models were developed in the present study using a forward modeling approach constrained by boundary conditions inferred from the paleo-hydrogeological evolution of the Horonobe area in Hokkaido, Japan. Apparent differences in transport behavior at the two boreholes location considered in this study, which were situated only about 1 km apart, appear to have resulted from relatively small differences in accessible porosity and hydraulic conductivity, which in turn may have been controlled by local differences in fracture density and fracture connectivity.
Takasaki, Koji; Yasumune, Takashi; Hashimoto, Makoto; Maeda, Koji; Kato, Masato; Yoshizawa, Michio; Momose, Takumaro
JAEA-Review 2019-003, 48 Pages, 2019/03
June 6, 2017, at Plutonium Fuel Research Facility in Oarai Research and Development Center of JAEA, when five workers were inspecting storage containers containing plutonium and uranium, resin bags in a storage container ruptured, and radioactive dust spread. Though they were wearing a half face mask respirator, they inhaled radioactive materials. In the evaluation of the internal exposure dose, the aerodynamic radioactive median diameter (AMAD) is an important parameter. We measured 14 smear samples and a dust filter paper with imaging plates, and estimated the AMAD by image analysis. As a result of estimating the AMAD, from the 14 smear samples, the AMADs are 4.3 to 11 m or more in the case of nitrate plutonium, and the AMADs are 5.6 to 14 m or more in the case of the oxidized plutonium. Also, from the dust filter paper, the AMAD is 3.0 m or more in the case of nitrate plutonium, and the AMAD is 3.9 m or more in the case of the oxidized plutonium.
Meigo, Shinichiro; Noda, Fumiaki*; Fujimori, Hiroshi*; Ikeda, Yujiro
Proceedings of ICANS-XVI, Volume 3, p.967 - 976, 2003/07
In J-PARC project, spallation target is irradiated by 3 GeV proton beam of 1 MW. Due to hands on maintenance for the proton beam lines, loss of proton beam is limited less than 1 W/m. Since it is difficult to predict the phase space distribution of the proton beam, we decided that the beam line have to be larger acceptance for 324 mrad, which is determined by the collimator located in the synchrotron. Distortion of proton beam is caused by the by the instability of angle at the extraction of 3-GeV synchrotron, miss alignment of the magnet, and un-uniformity of the magnet field. In this study, the distortion is calculated. In order to fit the conditions, the stability of extraction angles should be kept smaller than 0.2 mrad. As for the magnetic field, it is found that the uniformity should be kept better 5x10 and 2x10 for bending and quadruple magnets, respectively. It is also found the error of alignments should be limited smaller than 1.0 mm and 1.0 mrad.
Meigo, Shinichiro; Maekawa, Fujio; Kasugai, Yoshimi; Nakashima, Hiroshi; Ikeda, Yujiro; Watanabe, Noboru; Ino, Takashi*; Sato, Setsuo*; ASTE Collaboration
JAERI-Conf 2001-002, p.941 - 954, 2001/03
no abstracts in English
Peter, J. Collins
PNC TN9410 97-034, 35 Pages, 1997/04
While in the Reactor Physics Research Section of the Advanced Technology Division at OEC, I participated in the project to construct a data library for the demonstration fast breeder reactor (DFBR). This library would be produced using a combination of evaluated differential cross sections together with integral experimental data for fast reactors, so as to assure sufficiently accurate calculations for the DFBR designs. I had much experience of the design and use of experiments for the large-size cores at ZPPR under the title JUPITER which was performed under the USDOE/PNC joint agreement. My contribution here was mainly in extension of the experimental database to include the very-hard spectrum fast criticals from the Los Alamos National Laboratory (LANL). The data for these cores are described. Our work at ANLW with the GMADJ code, which is similar in effect to the ABLE code that we use at PNC, showed why many experiments are important in this project as well as those in the more obvious Pu/U oxide conventional cores which are of current interest for the DFBR. This point was not appreciated at PNC and is discussed here. The data from the fast spectrum critical experiments made at Los Alamos are described together with information that I have been able to find concerning the uncertainties. The main interest is these experiments has been for prediction of criticality. Consequently, the full covariance information that we would like has not been published. However, the uncertainty in the fuel content is, by far, the major contributor to the uncertainty. The LANL experiments have been a principal leg of the data testing for fast reactors for all versions of ENDF/B in the US. For our work, they provide measurements at Mev energies which are not available from the experiments in the softer-spectrum of the LMFBR.
Amano, Hikaru
Proc. of the 4th Int. Seminor of Liquid Scintillation Analysis, p.236 - 245, 1991/00
no abstracts in English
JAERI-M 7335, 88 Pages, 1977/10
no abstracts in English
Saeki, Masakatsu; Tachikawa, Enzo
Bulletin of the Chemical Society of Japan, 49(8), p.2214 - 2219, 1976/08
Times Cited Count:1no abstracts in English
Tschiersch, J.*; Yoshimura, Kazuya; Spielmann, V.*; Hurkamp, K.*; Iijima, Kazuki; Shinonaga, Taeko*; Miyahara, Kaname
no journal, ,
Inhalation dose depends on the kind and amount of inhaled radionuclides, but also on the size of radioactive particles and the solubility of the radionuclides in the lungs. Initial measurements during decontamination provide experimental data of the main parameters. These are particle size distribution with activity median aerodynamic diameter (AMAD) and geometric standard deviation and the solubility in the lungs. The dose assessment is performed according ICRP lung model using the computer code IMBA professional. Doses determined from measured parameters are compared to those using ICRP default values. Variability is studied and the range of potential inhalation dose is assessed.