Futemma, Akira; Sanada, Yukihisa; Sasaki, Miyuki; Kawasaki, Yoshiharu*; Iwai, Takeyuki*; Hiraga, Shogo*; Sato, Kazuhiko*; Haginoya, Masashi*; Matsunaga, Yuki*; Kikuchi, Hikaru*; et al.
JAEA-Technology 2021-020, 138 Pages, 2021/11
A large amount of radioactive material was released by the nuclear disaster of Fukushima Daiichi Nuclear Power Station (FDNPS), Tokyo Electric Power Company, caused by the Great East Japan Earthquake and the following tsunami on March 11, 2011. After the nuclear disaster, airborne radiation monitoring via manned helicopter has been utilized to grasp rapidly and widely the distribution of the radioactive materials surrounding FDNPS. We prepare the data of background radiation dose, geomorphic characteristics and the controlled airspace surrounding nuclear facilities of the whole country in order to make effective use of the monitoring technique as a way of emergency radiation monitoring and supply the results during an accident of a facility. This report is summarized that the knowledge as noted above achieved by the aerial radiation monitoring around Tsuruga and Mihama nuclear power station, research reactors in Kindai University Atomic Energy Research Institute and Institute for Integrated Radiation and Nuclear Science, Kyoto University. In addition, examination's progress aimed at introduction of airborne radiation monitoring via unmanned plane during nuclear disaster and the technical issues are summarized in this report.
Koyama, Shinichi; Nakagiri, Toshio; Osaka, Masahiko; Yoshida, Hiroyuki; Kurata, Masaki; Ikeuchi, Hirotomo; Maeda, Koji; Sasaki, Shinji; Onishi, Takashi; Takano, Masahide; et al.
Hairo, Osensui Taisaku jigyo jimukyoku Homu Peji (Internet), 144 Pages, 2021/08
JAEA performed the subsidy program for the "Project of Decommissioning and Contaminated Water Management (Development of Analysis and Estimation Technology for Characterization of Fuel Debris (Development of Technologies for Enhanced Analysis Accuracy and Thermal Behavior Estimation of Fuel Debris))" in 2020JFY. This presentation summarized briefly the results of the project, which will be available shortly on the website of Management Office for the Project of Decommissioning and Contaminated Water Management.
Kusaka, Ryoji; Kumagai, Yuta; Yomogida, Takumi; Takano, Masahide; Watanabe, Masayuki; Sasaki, Takayuki*; Akiyama, Daisuke*; Sato, Nobuaki*; Kirishima, Akira*
Journal of Nuclear Science and Technology, 58(6), p.629 - 634, 2021/06
Takahashi, Atsushi*; Chiba, Mirei*; Tanahara, Akira*; Aida, Jun*; Shimizu, Yoshinaka*; Suzuki, Toshihiko*; Murakami, Shinobu*; Koarai, Kazuma; Ono, Takumi*; Oka, Toshitaka; et al.
Scientific Reports (Internet), 11(1), p.10355_1 - 10355_11, 2021/05
Sato, Nobuaki*; Kirishima, Akira*; Watanabe, Masayuki; Sasaki, Takayuki*; Uehara, Akihiro*; Takeda, Shino*
Uran No Kagaku (II); Hoho To Jissen, 143 Pages, 2021/03
This book describes necessary facts when readers would have an opportunity to treat Uranium for experiments. In the content, the method section shows experimental facilities and equipment including method, and the practical section mentions solution and solid state experiments using Uranium and/or radioisotopes.
Goto, Akira; Sasaki, Akimichi*; Komatsu, Tetsuya; Miwa, Atsushi*; Terusawa, Shuji*; Kagohara, Kyoko*; Shimada, Koji
JAEA-Research 2020-013, 88 Pages, 2020/11
Improvement of the investigation techniques to identify active faults is important for the implementation of geological disposal projects from the viewpoint of avoiding locations where permeability increases due to fault displacement. Generally, the existence of active faults is confirmed by aerial photography interpretation of fault displacement topography, which is a topographical trace of fault movement, and on-site geological surveys. However, the investigation method for cases where the topographical traces are unclear is not sufficiently developed. Therefore, to improve existing topographical methods, this study deciphered lineaments up to the rank of poorly defined features, which are almost neglected in general active fault research. The investigation area is one of the geodetic strain concentration zone, called the southern Kyushu shear zone, where the seismogenic faults of the 1997 Kagoshima northwest earthquakes are concealed. We conducted aerial photography interpretation of 62 sheets of 1/25,000 topographic maps, and obtained 1,327 lineaments. Distribution density, direction and length of lineaments were also investigated with topographic and geologic information. As a result, it was clarified that the east-west lineaments in the south Kyushu shear zone predominate in the western part, and the lineaments are densely distributed in the aftershock distribution area of the Kagoshima northwest earthquake. Along with these results, we have compiled a catalog of typical 13 lineaments based on combinations of clarity, direction, length and geomorphic characters of lineaments.
Kobayashi, Taishi*; Sasaki, Takayuki*; Kitamura, Akira
Journal of Chemical Thermodynamics, 138, p.151 - 158, 2019/11
The effect of -isosaccharinic acid (ISA) on the solubility and redox of tetravalent and hexavalent uranium (U(IV), U(VI)) was investigated in the hydrogen ion concentration (pH) range of 613 and at total ISA concentration ([ISA]) = 1010 mol/dm. The dependence of U(IV) solubility on pH and [ISA] suggested the existence of U(OH)(ISA) as a dominant species within the investigated pH range of 612. For the U(VI)-ISA system, UO(OH)(ISA) was suggested as a dominant species at pH 713. The formation constants of the U(IV)-ISA and U(VI)-ISA complexes were determined by least-squares fitting of the solubility data. The solubility of U(IV) and U(VI) in the presence of ISA and its effect on the redox behavior were thermodynamically interpreted based on the obtained constants.
Miwa, Kazuji; Terasaka, Yuta; Ochi, Kotaro; Futemma, Akira; Sasaki, Miyuki; Hirouchi, Jun
Nihon Genshiryoku Gakkai-Shi ATOMO, 61(9), p.687 - 691, 2019/09
This report summarizes the contents of the session of the Health Physics and Environment Science Division, which was held in Atomic Energy Society of Japan 2019 Spring Meeting. In this session, six students and young researchers who engaged in the field of nuclear energy and radiation gave a lecture about health physics and environmental science research through their expertise. After the all presentations end, we took discussion time about the issues and future development in this field with all attendees. In this report, we summarized each lecture outline and discussion contents.
Rai, D.*; Kitamura, Akira; Altmaier, M.*; Rosso, K. M.*; Sasaki, Takayuki*; Kobayashi, Taishi*
Journal of Solution Chemistry, 47(5), p.855 - 891, 2018/05
We have critically reviewed experimental data for Zr hydrolysis constant values for formation of several mononuclear and polynuclear species and a solubility product value for ZrO(am). We have determined new/revised values for the formation constants of Zr(OH), Zr(OH)(aq), Zr(OH), Zr(OH) and CaZr(OH), and the solubility product for ZrO(am) after the critical review.
Ueno, Yasuhiro*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 238(1), p.14_1 - 14_6, 2017/11
Sasaki, Takayuki*; Kokami, Takayuki*; Kobayashi, Taishi*; Kirishima, Akira*; Murakami, Hiroaki; Amano, Yuki; Mizuno, Takashi; Iwatsuki, Teruki; Sasamoto, Hiroshi; Miyakawa, Kazuya
Journal of Nuclear Science and Technology, 54(3), p.373 - 381, 2017/03
Trace amounts of natural thorium and uranium in deep groundwater were investigated at two underground research laboratories situated at Horonobe and Mizunami, Japan. The groundwater was sampled from underground boreholes, and the colloid contribution was checked by in situ two size-fractionated ultrafiltration systems. A decrease in the concentration after in situ filtration suggested the presence of natural colloids and suspended matter that were carriers of a portion of the elements. The result of the Th and U concentrations in groundwater after 10 kDa filtration was analyzed thermodynamically using existing hydrogeological and geochemical data such as the mineral components in the groundwater at a given pH, ionic strength, concentration of co-existing ions, redox potential, and solid phase assumed. A crystalline solid phase made the solubility very low compared with that of the amorphous phase, and the solubility agreed well with the concentrations measured.
Kirishima, Akira*; Kuno, Atsushi*; Amamiya, Hiroki; Kubota, Takumi*; Kimuro, Shingo*; Amano, Yuki; Miyakawa, Kazuya; Iwatsuki, Teruki; Mizuno, Takashi; Sasaki, Takayuki*; et al.
Chemosphere, 168, p.798 - 806, 2017/02
For better understanding of the migration behavior of minor actinides (MA) in deep groundwater, the interaction of doped rare earth elements (REEs) and components in Horonobe deep groundwater was studied. Appx. 10 ppb of rare earth elements, i.e., Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er, Tm and Yb were doped to the sample groundwater collected from a packed sections in borehole drilled from 140 m depth experiment drift of Horonobe underground research laboratory (URL), Hokkaido, Japan. Then, that groundwater was sequentially filtrated by 0.2 micron pore filter, 10 kDa, 3 kDa and 1 kDa of nominal molecular weight limit (NMWL) ultrafilters by keeping inert condition. After that, the filtrate solutions were analyzed by ICP-MS to determine the concentrations of retained REEs at each filtration steps, while the used filters were analyzed by the neutron activation analysis (NAA) and TOF-SIMS element mapping to know the amount and chemical speciation of trapped fraction of the REEs on each filter. A remarkable relation between the retention ratios of REEs in the filtrate solutions and the ionic radius was observed, i.e., smaller rare earth element solves more in liquid phase under the Horonobe groundwater condition. NAA and TOF-SIMS analyses revealed that certain portions of REEs were trapped by 0.2 micron pore filters as rare earth phosphates which corresponded with the predicted predominant species by a chemical equilibrium calculation for the Horonobe groundwater condition, while small portions of colloidal REEs were trapped by 10 kDa and 3 kDa NMWL ultrafilters. The result suggested that phosphate anion plays an important role in the chemical behavior of REEs in saline (seawater based) groundwater, which could be referred for the prediction of migration behavior of trivalent actinide released from the repository of radioactive waste in far future.
Kobayashi, Taishi*; Teshima, Takeshi*; Sasaki, Takayuki*; Kitamura, Akira
Journal of Nuclear Science and Technology, 54(2), p.233 - 241, 2017/02
Zr solubility in the presence of gluconic acid (GLU) and isosaccharinic acid (ISA) was investigated as a function of hydrogen ion concentration (pH) and the total concentration of GLU or ISA. The dependence of the increase in Zr solubility on the pH and GLU concentration suggested the existence of Zr(OH)(GLU) in the neutral pH region and Zr(OH)(GLU)(GLU) in the alkaline pH region above pH 10 as the dominant species in the presence of 10 - 10 mol/dm (M) GLU. In the presence of ISA, the dominant species Zr(OH)(ISA) and Zr(OH)(ISA)(ISA) were proposed to occur in the neutral and alkaline pH regions, similar to those found in the presence of GLU. From X-ray diffraction analysis, the solubility-limiting solid phase in the presence of GLU and ISA was considered to be Zr(OH)(am). The formation constants of the Zr gluconate and isosaccharinate complexes were determined by least squares fitting analysis of the solubility data, and the obtained values were discussed in comparison with those of tetravalent actinides.
Strasser, P.*; Aoki, Masaharu*; Fukao, Yoshinori*; Higashi, Yoshitaka*; Higuchi, Takashi*; Iinuma, Hiromi*; Ikedo, Yutaka*; Ishida, Keiichi*; Ito, Takashi; Iwasaki, Masahiko*; et al.
Hyperfine Interactions, 237(1), p.124_1 - 124_9, 2016/12
Rai, D.*; Kitamura, Akira; Rosso, K. M.*; Sasaki, Takayuki*; Kobayashi, Taishi*
Radiochimica Acta, 104(8), p.583 - 592, 2016/08
Solubility studies were conducted with HfO(cr) solid as a function of acid concentrations. These studies involved (1) using two different amounts of the solid phase, (2) acid washing the bulk solid phase, (3) preheating the solid phase to 1400 C, and (4) heating amorphous HfO(am) suspensions to 90 C to ascertain whether the HfO(am) converts to HfO(cr) and to determine the solubility from the oversaturation direction. Based on the results of these treatments it is concluded that the HfO(cr) contains a small fraction of less crystalline, but not amorphous, material [HfO(lcr)] and this, rather than the HfO(cr), is the solubility-controlling phase in the range of experimental variables investigated in this study. The solubility data are interpreted using both the Pitzer and SIT models. The log of the solubility product of HfO(cr) is estimated. The observation of a small fraction of less crystalline higher solubility material is consistent with the general picture that mineral surfaces are often structurally and/or imperfect leading to a higher solubility than the bulk crystalline solid. This study stresses the urgent need, during interpretation of solubility data, of taking precautions to make certain that the observed solubility behavior for sparingly-soluble solids is assigned to the proper solid phase.
Sasaki, Akira; Nishihara, Katsunobu*; Sunahara, Atsushi*; Nishikawa, Takeshi*
Proceedings of SPIE, Vol.9776, p.97762C_1 - 97762C_6, 2016/03
For the improvement of efficiency and output of the laser pumped plasma (LPP) extreme ultra-violet (EUV) light source, we present a hydrodynamics model of laser irradiated Sn targets. The model takes liquid/solid to gas transition and mixed phase condition of the flow into account for the calculation of the distribution of the particles produced by the pre-pulse laser irradiation and optimization of the EUV source. Firstly, we investigate the mechanisms of the fragmentation of the target and particle emission, including the effect of the equation of state of Sn, and secondly, an applicable model is proposed based on the analysis.
Sasaki, Akira; Kato, Susumu*; Takahashi, Eiichi*; Kishimoto, Yasuaki*; Fujii, Takashi*; Kanazawa, Seiji*
Japanese Journal of Applied Physics, 55(2), p.026101_1 - 026101_10, 2016/02
A percolation model of discharge, which can reproduce stochastic behaviors of initial partial discharge to the growth of a stepped leader, is presented. The model uses macroscopic cells, from which a network of electric circuits is defined, and the spatial and temporal evolutions of the electric field and current in the discharge medium are calculated. For each cell, one of two states, either insulator or conductor, which corresponds to neutral gas or ionized plasmas, respectively, is decided. The decision is made on the basis of probability for each calculation cell at each time step, taking the effects of local electric field and current, which enhance ionization and sustain the discharge channel, respectively, into account. The stochastic behavior of discharge is discussed, in conjunction with the characteristic feature of ionization, that is, the ionization occurs not only ahead of the streamer tip where the electric field is enhanced but randomly in the discharge medium.
Nakamoto, Tatsushi*; Sugano, Michinaka*; Xu, Q.*; Kawamata, Hiroshi*; Enomoto, Shun*; Higashi, Norio*; Idesaki, Akira; Iio, Masami*; Ikemoto, Yukio*; Iwasaki, Ruri*; et al.
IEEE Transactions on Applied Superconductivity, 25(3), p.4000505_1 - 4000505_5, 2015/06
Recently, development of superconducting magnet system with high radiation resistance has been demanded for application in accelerator facilities such as CERN LHC. In order to realize superconducting magnet system with high radiation resistance, it is necessary to develop electrical insulator with high radiation resistance because the electrical insulator is made of organic materials whose radiation resistance is inferior to that of inorganic materials. We developed a glass fiber reinforced plastic with bismaleimide-triazine resin. The developed material showed excellent radiation resistance; the material evolved gases of 510 mol/g and maintained flexural strength of 640MPa (90% of initial value).
Sasaki, Yuji; Saeki, Morihisa; Sugo, Yumi; Ikeda, Yasuhisa*; Kawasaki, Takeshi*; Suzuki, Tomoya*; Ohashi, Akira*
Solvent Extraction Research and Development, Japan, 22(1), p.37 - 45, 2015/05
An extractant, methylimino-bis--dioctylacetamide (MIDOA), was used for the extraction of soft acid metals. It was found that MIDOA can extract not only Cr(VI), Mo(VI), W(VI), Tc(VII) and Re(VII), whose metals can form the oxonium anions due to their high oxidation states, but also other metal cations, like Nb(V), Ta(V) and Pd(II). Analogous compounds, imino-bis--dioctylacetamide (IDOA) and methylimino-bis--di-2-ethylhexylacetamide (MIDEHA), are synthesized and compared for their extractability. It is clear that these extractants have almost same or lower values than those for MIDOA. In order to examine the effect on extractability with different donor atoms, TODGA (-tetraoctyl-diglycolamide) and TDGA (-tetraoctyl-tyiodiglycolamide) having oxygen and sulfur donor are employed. The comparison of their extractabilities suggests that the trend of Pd and Re extraction is N S O and N O S, respectively.
Sasaki, Akira; Nishimura, Hiroaki*; Onishi, Naofumi*
Purazuma, Kaku Yugo Gakkai-Shi, 91(2), p.166 - 167, 2015/02
no abstracts in English