Tochio, Daisuke; Nagasumi, Satoru; Inoi, Hiroyuki; Hamamoto, Shimpei; Ono, Masato; Kobayashi, Shoichi; Uesaka, Takahiro; Watanabe, Shuji; Saito, Kenji
JAEA-Technology 2021-014, 80 Pages, 2021/09
In response to the new regulatory standards established in response to the accident at TEPCO's Fukushima Daiichi Nuclear Power Station in March 2011, measures and impact assessments related to internal flooding at HTTR were carried out. In assessing the impact, considering the characteristics of the high-temperature gas-cooled reactor, flooding due to assumed damage to piping and equipment, flooding due to water discharge from the system installed to prevent the spread of fire, and flooding due to damage to piping and equipment due to an earthquake. The effects of submersion, flooding, and flooding due to steam were evaluated for each of them. The impact of the overflow of liquids containing radioactive materials outside the radiation-controlled area was also evaluated. As a result, it was confirmed that flooding generated at HTTR does not affect the safety function of the reactor facility by taking measures.
Watanabe, Yukinobu*; Sadamatsu, Hiroki*; Araki, Shohei*; Nakano, Keita*; Kawase, Shoichiro*; Kin, Tadahiro*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; et al.
EPJ Web of Conferences, 239, p.20012_1 - 20012_4, 2020/09
Accelerator-based neutron sources induced by deuteron beams are attractive for study of nuclear transmutation of radioactive waste as well as radiation damage for fusion reactor materials. In the present work, we have carried out a Double Differential cross section (DDX) measurement for Li at 200 MeV in the Research Center for Nuclear Physics (RCNP), Osaka University. A deuteron beam accelerated to 200 MeV was transported to the neutron experimental hall and focused on a thin Li target. Emitted neutrons from the target were detected by two different-size EJ301 liquid organic scintillators located at two distances of 7 m and 20 m, respectively. The neutron DDXs were measured at six angles from 0 to 25). The neutron detection efficiencies of the detectors were calculated by SCINFUL-QMD code. We will present the results of the present DDX measurement and compare them with theoretical model calculations with DEURACS and PHITS.
Wang, H.*; Otsu, Hideaki*; Chiga, Nobuyuki*; Kawase, Shoichiro*; Takeuchi, Satoshi*; Sumikama, Toshiyuki*; Koyama, Shumpei*; Sakurai, Hiroyoshi*; Watanabe, Yukinobu*; Nakayama, Shinsuke; et al.
Communications Physics (Internet), 2(1), p.78_1 - 78_6, 2019/07
Searching for effective pathways for the production of proton- and neutron-rich isotopes through an optimal combination of reaction mechanism and energy is one of the main driving forces behind experimental and theoretical nuclear reaction studies as well as for practical applications in nuclear transmutation of radioactive waste. We report on a study on incomplete fusion induced by deuteron, which contains one proton and one neutron with a weak binding energy and is easily broken up. This reaction study was achieved by measuring directly the cross sections for both proton and deuteron for Pd at 50 MeV/u via inverse kinematics technique. The results provide direct experimental evidence for the onset of a cross-section enhancement at high energy, indicating the potential of incomplete fusion induced by loosely-bound nuclei for creating proton-rich isotopes and nuclear transmutation of radioactive waste.
Yamasaki, Atsushi*; Fujiwara, Hidenori*; Tachibana, Shoichi*; Iwasaki, Daisuke*; Higashino, Yuji*; Yoshimi, Chiaki*; Nakagawa, Koya*; Nakatani, Yasuhiro*; Yamagami, Kohei*; Aratani, Hidekazu*; et al.
Physical Review B, 94(11), p.115103_1 - 115103_10, 2016/11
In this study, we systematically investigate three-dimensional(3D) momentum-resolved electronic structures of Ruddlesden-Popper-type iridium oxides SrIrO using soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES). Our results provide direct evidence of an insulator-to-metal transition that occurs upon increasing the dimensionality of the IrO-plane structure. This transition occurs when the spin-orbit-coupled = 1/2 band changes its behavior in the dispersion relation and moves across the Fermi energy. By scanning the photon energy over 350 eV, we reveal the 3D Fermi surface in SrIrO and -dependent oscillations of photoelectron intensity in SrIrO. To corroborate the physics deduced using low-energy ARPES studies, we propose to utilize SX-ARPES as a powerful complementary technique, as this method surveys more than one whole Brillouin zone and provides a panoramic view of electronic structures.
Sakai, Kenji; Sakamoto, Shinichi; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; Naoe, Takashi; Kasugai, Yoshimi; Tatsumoto, Hideki; et al.
JAEA-Technology 2011-039, 121 Pages, 2012/03
This report investigates the behavior, damage and restoration of a neutron source station of the MLF at the Great East Japan Earthquake and verified the safety design for emergency accidents in the neutron source station. In the MLF, after an occurrence of the Earthquake, strong quakes were detected at the instruments, the external power supply was lost, all of the circulators shut down automatically, and the hydrogen gas was released. The leakages of mercury, hydrogen and radio-activation gases did not occur. While, the quakes made gaps between the shield blocks and ruptured external pipe lines by subsidence around the building. But significant damages to the components were not found though the pressure drop of compressed air lines influenced on a target trolley lock system and so on. These results substantiated the validity of the safety design for emergency accidents in the source station, and suggested several points of improvement.
Sakai, Kenji; Futakawa, Masatoshi; Takada, Hiroshi; Sakamoto, Shinichi; Maekawa, Fujio; Kinoshita, Hidetaka; Seki, Masakazu; Haga, Katsuhiro; Kogawa, Hiroyuki; Wakui, Takashi; et al.
Proceedings of 20th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-20) (USB Flash Drive), 6 Pages, 2012/03
This report investigates behaviors and damages of each component in a neutron target station of the MLF at the J-PARC at the time of the Great East Japan Earthquake (GEJE). At the date of the GEJE, in the MLF, strong quakes were detected at several instruments, an external power supply were lost, all of the circulation systems were shut down automatically, and a hydrogen gas was released as planned. Leakage of activation liquids and gases did not occur. While, the quakes made gaps between shield blocks and ruptured external pipe lines for air and water by subsidence. But significant damages on the components of the target station were not found though a loss of compressed air supply affected lock systems with air cylinders and pneumatic operation values. These results substantiated a validity of safety design on the target station for emergency accidents.
Sato, Shoichi*; Ichimura, Makoto*; Yamaguchi, Yusuke*; Katano, Makoto*; Imai, Yasutaka*; Murakami, Tatsuya*; Miyake, Yuichiro*; Yokoyama, Takuro*; Moriyama, Shinichi; Kobayashi, Takayuki; et al.
Plasma and Fusion Research (Internet), 5, p.S2067_1 - S2067_4, 2010/12
Ion cyclotron emissions (ICEs) due to deuterium-deuterium fusion-product (FP) ions on JT-60U are studied. ICE due to H-ions is identified from the difference of the toroidal wave number of 2nd ICE(D). The parameter dependence for the appearance of ICE(H) is investigated from the experimental conditions and also is studied by using "Escape Particle Orbit analysis Code (EPOC)".
Tonoike, Kotaro; Yamamoto, Toshihiro; Miyoshi, Yoshinori; Uchiyama, Gunzo; Watanabe, Shoichi*
Journal of Nuclear Science and Technology, 46(4), p.354 - 365, 2009/04
A series of critical experiments were performed using heterogeneous cores at the Static Experiment Critical Facility in Japan Atomic Energy Agency in order to obtain systematic benchmark data concerning dissolving process in a reprocessing plant. Focusing on the introduction of the burn-up credit, critical mass measurement was conducted for a combination of uranium dioxide fuel rods (5wt% U) and uranyl nitrate solution (6wt% U) poisoned with pseudo fission product (FP) elements - samarium, cesium, rhodium, and europium. Fuel rods were arrayed with an 1.5-cm lattice interval in the poisoned fuel solution in a 60-cm diameter cylindrical tank. The uranium concentrations of the solution was roughly kept at about 320gU/L, and the FP element concentrations were adjusted to be equivalent to a burn-up of about 30GWd/t. The result provides basic experimental data for validation of computational methods to evaluate a reactivity effect of each FP element, as well as benchmark criticality data for validation of neutron multiplication factor calculation of heterogeneous systems of spent fuel. In the report, detail of the experiments and its benchmark models will be presented as well as the procedure and the result of separate reactivity worth evaluation for each FP element. The experimental result and the computational evaluation will also be compared.
Maekawa, Fujio; Oikawa, Kenichi; Harada, Masahide; Kai, Tetsuya; Meigo, Shinichiro; Kasugai, Yoshimi; Oi, Motoki; Sakai, Kenji; Teshigawara, Makoto; Hasegawa, Shoichi; et al.
Nuclear Instruments and Methods in Physics Research A, 600(1), p.335 - 337, 2009/02
A neutron beam line (BL10) of JSNS, NOBORU, has been constructed in the Materials and Life Science Experimental Facility (MLF) at J-PARC. A primal mission of NOBORU is to study neutronic performance of JSNS. We will measure the memorable first neutron pulse of JSNS at the Day-one by using NOBORU, and then measure neutron pulse shape, spectrum, intensity distribution, etc. for facility diagnostics. Since NOBORU also has an aspect as a test port, it welcomes trial uses to develop innovative instruments. Trial experiments to demonstrate several innovative instruments at NOBORU are under planning.
Oikawa, Kenichi; Maekawa, Fujio; Harada, Masahide; Kai, Tetsuya; Meigo, Shinichiro; Kasugai, Yoshimi; Oi, Motoki; Sakai, Kenji; Teshigawara, Makoto; Hasegawa, Shoichi; et al.
Nuclear Instruments and Methods in Physics Research A, 589(2), p.310 - 317, 2008/05
NOBORU, NeutrOn Beam-line for Observation and Research Use, has been constructed in the Materials and Life Science Facility (MLF) of J-PARC. NOBORU is designed to "Observe" a 1 MW Japan Spallation Neutron Source (JSNS), i.e., to study the neutronic performance of JSNS. NOBORU also will be used for "Research" activities, i.e., as a test port for R&D activities and trial users who have new ideas. In this paper, the design and application of NOBORU are described, and its expected performance is investigated by Monte Carlo simulations.
Tonoike, Kotaro; Miyoshi, Yoshinori; Uchiyama, Gunzo; Watanabe, Shoichi*; Yamamoto, Toshihiro*
Proceedings of 8th International Conference on Nuclear Criticality Safety (ICNC 2007), p.222 - 227, 2007/05
In order to obtain systematic benchmark criticality data concerning dissolving process in a reprocessing plant for LWR spent fuel, a series of critical experiments were performed using heterogeneous cores at the Static Experiment Critical Facility (STACY) in Japan Atomic Energy Agency (JAEA). Focusing on the introduction of the burn-up credit to the process, critical mass measurement was conducted for a combination of uranium fuel rods and uranium solution where pseudo fission product (FP) materials were doped. In this report, the "pseudo FP materials" means elements such as Sm, Cs, Rh and Eu whose isotopic composition is natural but which contains some FP nuclide(s). The result is going to provide basic experimental data for validation of computational methods to evaluate a reactivity effect of each FP material, as well as benchmark criticality data for validation of neutron multiplication factor calculation of heterogeneous systems of spent fuel. In the report, detail of the experiments including a differential reactivity worth curve over the solution level variation is going to be provided as well as the procedure and the result of separate reactivity worth evaluation of each pseudo FP material. Comparison of the experimental result and the computational evaluation will also be presented.
Maekawa, Fujio; Oikawa, Kenichi; Harada, Masahide; Kai, Tetsuya; Meigo, Shinichiro; Kasugai, Yoshimi; Oi, Motoki; Sakai, Kenji; Teshigawara, Makoto; Hasegawa, Shoichi; et al.
Proceedings of 18th Meeting of the International Collaboration on Advanced Neutron Sources (ICANS-18) (CD-ROM), p.118 - 126, 2007/00
One of 23 neutron beam lines of JSNS, NOBORU, has been assigned to the Neutron Facility Group of JAEA. The primary mission of NOBORU is to investigate neutronic performance of JSNS while it can accommodate various trial research experiments. This paper describes an experimental program by using NOBORU mostly in an on-beam commissioning period of JSNS after the first proton beam acceptance in 2008. Topics for the primary mission to be studied are as follows; relationships between operating parameters of JSNS and neutronic performance, acquisition of beam parameters for users, confirmation of integrity in main components of JSNS, validation of neutronic designs, and research and development on measuring techniques. In addition, we are interested in radiography, introduction of a high-pressure instrument and eV neutron spectroscopy, and also welcome trial uses to bring out new research activities.
Tsukamoto, Takashi*; Nakanishi, Hiromi*; Kiyomiya, Shoichiro*; Watanabe, Satoshi; Matsuhashi, Shimpei; Nishizawa, Naoko*; Mori, Satoshi*
Soil Science and Plant Nutrition, 52(6), p.717 - 725, 2006/12
Okuno, Hiroshi; Suyama, Kenya; Takahashi, Satoshi*; Watanabe, Shoichi*; Tonoike, Kotaro; Miyoshi, Yoshinori
Transactions of the American Nuclear Society, 95(1), p.283 - 284, 2006/11
no abstracts in English
Mirvaliev, R.*; Watanabe, Masayuki; Matsumura, Tatsuro; Tachimori, Shoichi*; Takeshita, Kenji*
Journal of Nuclear Science and Technology, 41(11), p.1122 - 1124, 2004/11
Transmutation is a technology aimed to reduce HLW from reprocessing process. Minor actinides in the HLW will be converted to short-lived nuclides. However, lanthanides in HLW adversely affects on the efficiency of the transmutation. It is well known that separating An(III) and Ln(III) is very difficult because of their similarity of chemical properties. Therefore, the separation is one of the essential subjects to establish the transmutation technology. Considerable efforts have been devoted to the development of new extractants for the separation. N,N,N',N'-tetrakis(2-methylpyridyl)ethylenediamine (TPEN) demonstrates 100-fold preference for Am(III) over Ln(III) between stability constants with the ions in the aqueous phase. We have reported that Am(III) was selectively extracted from the aqueous phase containing Ln(III) by TPEN in nitrobenzene system and synergistic system with TPEN and D2EHPA in octanol. This work presents our recent results that Am(III) is separated from Eu(III) by a synergistic extraction system with TPEN and decanoic acid diluted with 1-octanol.
Watanabe, Shoichi; Yamamoto, Toshihiro; Miyoshi, Yoshinori
Transactions of the American Nuclear Society, 91, p.431 - 432, 2004/11
Temperature effect is a main factor which affects the transient characteristics at a criticality accident. A series of reactivity effects due to changes in fuel temperatures were measured for two kinds of STACY heterogeneous lattice configurations. The core was composed of LWR-type fuel rod array and low-enriched uranyl-nitrate-solution concerning the dissolver of the reprocessing facility for LWR spent fuel. The critical solution heights at various solution temperatures were measured. From the change of the critical water height with fuel temperature, the reactivity effect was evaluated by a critical-solution-level worth method. The temperature effect was also calculated by using SRAC and the transport calculation code TWODANT. The experimental value was estimated to be -2.0 cent/C for the case "2.1cm-pitch", and -2.5 cent/C for the case "1.5cm-pitch". The calculated results gave agreement with the experiments within 10%.
Watanabe, Masayuki; Mirvaliev, R.*; Tachimori, Shoichi; Takeshita, Kenji*; Nakano, Yoshio*; Morikawa, Koshi*; Chikazawa, Takahiro*; Mori, Ryohei*
Solvent Extraction and Ion Exchange, 22(3), p.377 - 390, 2004/06
The synergistic extraction with N,N,N',N'-tetrakis(2-methylpyridyl)-ethylenediamine (TPEN) and di(2-ethylhexyl)phosphoric acid (D2EHPA) demonstrates a good selectivity for Am(III) over macro amount of Ln(III) in 1-octanol. The maximum apparent separation factor, which is defined as the ratio of the distribution ratio of Am(III) to that of Eu(III), is ca. 80 while the molar fraction between D2EHPA and TPEN is 2.0. This ratio is corresponding to the result of the spectrophotometric titration, which indicates that TPEN and D2EHPA form an aggregate in 1-octanol and two D2EHPA molecules coordinate to Eu(III) TPEN complex, [Eu(TPEN)]. In the present study, the association of D2EHPA and TPEN is one of the most important factors for the synergistic extraction and the complexation of TPEN and D2EHPA with Eu(III).
Tonoike, Kotaro; Yamamoto, Toshihiro; Watanabe, Shoichi; Miyoshi, Yoshinori
Journal of Nuclear Science and Technology, 41(2), p.177 - 182, 2004/02
As a part of the development of a subcriticality monitoring system, a system which has a time series data acquisition function of detector signals and a real time evaluation function of alpha value with the Feynman- method was established, with which the kinetic parameter (alpha value) was measured at the STACY heterogeneous core. The Hashimoto's difference filter was implemented in the system, which enables the measurement at a critical condition. The measurement result of the new system agreed with the pulsed neutron method.
Watanabe, Masayuki; Nankawa, Takuya*; Yamada, Teppei*; Kimura, Takaumi; Namiki, Kosuke*; Murata, Masaki*; Nishihara, Hiroshi*; Tachimori, Shoichi
Inorganic Chemistry, 42(22), p.6977 - 6979, 2003/11
A tripodal ligand, tris(2-pyridyl)carbinol affords a novel tetradentate coordination mode in homodinuclear lanthanide complexes, which exhibit remarkably short distance between the metal ions. Strong fluorescence of Eu(III) and Tb(III) complexes with the ligand demonstrate that the ligand has a suitable excited state for energy transfer from the ligand to Eu(III) and Tb(III) center.
Watanabe, Shoichi; Yamane, Yuichi; Miyoshi, Yoshinori
JAERI-Tech 2003-045, 73 Pages, 2003/03
Since exact information is not always acquired in the criticality accident of fuel-solution, parametric survey calculations are required for grasping behaviors of the thermal-hydraulics. On the other hand, the practical methods of the calculation which can reduce the computation time with allowable accuracy will be also required, since the conventional method takes a long calculation time. In order to fulfill the requirement, a three-dimensional nuclear-kinetics analysis code considering thermal-hydraulic based on the multi-region kinetic equations with one-group neutron energy was created by incorporating the thermal-hydraulics analysis code PHOENICS as a subroutine. The computation time of the code was shortened by separating time mesh intervals of the nuclear- and heat-calculations from that of the hydraulics calculation, and by regulating automatically the time mesh intervals in proportion to power change rate. A series of analysis were performed for the natural-cooling characteristic test using TRACY in which the power changed slowly for 5 hours after the transient power resulting from the reactivity insertion of a 0.5 dollar. It was found that the code system was able to calculate within the limit of practical time, and acquired the prospect of reproducing the experimental values considerably for the power and temperature change.