Yamaguchi, Toshio*; Nishino, Masaaki*; Yoshida, Koji*; Takumi, Masaharu*; Nagata, Kiyofumi*; Hattori, Takanori
European Journal of Inorganic Chemistry, 2019(8), p.1170 - 1177, 2019/02
Neutron diffraction measurements of an aqueous 2 mol dm CaCl solutions in DO have been made at 1 GPa, 298 K as well as 0.1 MPa, 298 K. The experimental structure factors are subjected to Empirical Potential Structure Refinement (EPSR) modeling to reveal the ion hydration and association and solvent water at the atomic level. About seven water molecules surround Ca at the Ca-O and Ca-D distances of 2.44 and 3.70 , respectively, at both pressures, suggesting no significant pressure effect on the cation hydration. On the other hand, the Cl ion shows a drastic change in water oxygen coordination from 7 at 0.1 MPa to 14 at 1 GPa, accompanied by shortening of Cl-O distance from 3.18 to 3.15 . However, the number of water hydrogen atoms around Cl does not change significantly as 6.0 6.7 with shortening Cl-D distance from 2.22 to 2.18 on compression. The pressure effect on the solvent water structure is also drastic as an increase in water oxygen atoms of 4.7 at the O-O distance of 2.79 at 0.1 MPa to 10.3 at 2.85 at 1 GPa. The number of water hydrogen atoms, however, does not change as 1.2 at the O-D distance of 1.74 for both pressures, demonstrating the presence of the OD hydrogen bonds which are significantly bent at 1 GPa at 298 K. This change of hydrogen bonds in water with pressure probably causes the drastic increase in water oxygen atoms around Cl.
Sasa, Toshinobu; Saito, Shigeru; Obayashi, Hironari; Sugawara, Takanori; Wan, T.; Yamaguchi, Kazushi*; Yoshimoto, Hidemitsu
NEA/CSNI/R(2017)2 (Internet), p.111 - 116, 2017/06
Japan Atomic Energy Agency (JAEA) proposes to reduce the environmental impact caused from high-level radioactive waste by using Accelerator-driven system (ADS). To realize ADS, JAEA plans to build the Transmutation Experimental Facility (TEF) within the framework of J-PARC project. For the JAEA-proposed ADS, lead-bismuth eutectic alloy (LBE) is adopted as a coolant for subcritical core and spallation target. By using TEF in J-PARC, we are planning to solve technical difficulties for LBE utilization by completion of the data for the design of ADS. The 250kW LBE spallation target will be located in TEF facility to prepare material irradiation database. Various R&Ds for important technologies required to build the facilities are investigated such as oxygen content control, instruments development, remote handling techniques for target maintenance, and spallation target design. The large scale LBE loops for 250kW target mock up and material corrosion studies are also manufactured and ready for various experiments. The latest status of 250kW LBE spallation target optimization will be described in the presentation.
Nishihara, Kenji; Tazawa, Yujiro; Inoue, Akira; Sugawara, Takanori; Tsujimoto, Kazufumi; Sasa, Toshinobu; Obayashi, Hironari; Yamaguchi, Kazushi; Kikuchi, Masashi*
JAEA-Technology 2015-051, 47 Pages, 2016/03
This report summarizes fabrication and test results of a testing equipment for fuel cooling that is a component of the testing equipment for remote-handling of highly-radioactive MA fuels in the transmutation physics experimental facility (TEF-P) planned in the J-PARC. Evaluation formula of pressure drop and temperature increase used in the design of TEF-P was validated by the test, and, feasibility of cooling concept was confirmed.
Sugawara, Takanori; Yamaguchi, Kazushi
JAEA-Technology 2015-022, 21 Pages, 2015/08
The oxygen sensors to measure the oxygen concentration in liquid LBE (lead-bismuth eutectic) were fabricated for future use in LBE-cooled ADS (accelerator-driven system) or LBE test loops. Two types of oxygen sensors were fabricated and used for the measurement under the oxygen saturated condition. Through the measurement experiment, it was confirmed that the electromotive force (EMF) from Pt-type sensor was reliable under 350C to 450C LBE temperature. The Pt-type sensor will be the first candidate for the use in LBE test loops.
Sasa, Toshinobu; Takei, Hayanori; Saito, Shigeru; Obayashi, Hironari; Nishihara, Kenji; Sugawara, Takanori; Iwamoto, Hiroki; Yamaguchi, Kazushi; Tsujimoto, Kazufumi; Oigawa, Hiroyuki
NEA/CSNI/R(2015)2 (Internet), p.85 - 91, 2015/06
Nuclear transmutation got much interested as an effective option of nuclear waste management. Japan Atomic Energy Agency (JAEA) proposes the transmutation of minor actinides (MA) by accelerator-driven system (ADS) using lead-bismuth alloy (Pb-Bi). To obtain the data for ADS design, JAEA plans to build a Transmutation Experimental Facility (TEF) in the J-PARC project. TEF consists of two buildings, an ADS target test facility (TEF-T) with 400MeV-250kW Pb-Bi target, and a Transmutation Physics Experimental Facility (TEF-P), which set up a fast critical assembly driven by low power proton beam with MA fuel. In TEF-T, irradiation test for materials, and engineering tests for Pb-Bi target operation will be performed. Various research plans such as nuclear data measurements have been proposed and layout of the experimental hall are underway. In the presentation, roadmap to establish the ADS transmutor and latest design activities for TEF construction will be summarized.
Hamada, Kazuya; Kawano, Katsumi; Ebisawa, Noboru; Nakajima, Hideo; Yano, Yoshitaka*; Yamaguchi, Takanori*
Proceedings of 24th International Cryogenic Engineering Conference (ICEC 24) and International Cryogenic Materials Conference 2012 (ICMC 2012) (CD-ROM), p.559 - 562, 2012/05
The Japan Atomic Energy Agency (JAEA) has the responsibility to procure 25% of the ITER Toroidal Field Coil conductors and 100% of Central Solenoid Conductor as the Japanese Domestic Agency (JADA) in the ITER project. The TF conductor is composed of 900 NbSn superconducting strands and 522 Cu strands protected by a circular sheath tube (jacket) with an outer diameter of 43.7 mm. The TF conductor has a central spiral cooling tube and a coolant flows into the cable space and the central channel in parallel. JAEA has measured a pressure drop characteristic of more than 20 TF conductors having different length using nitrogen gas at room temperature as a part of acceptance test. The measurement results are normalized to friction factor as a function of Reynolds number to check the difference of each other. The results show the normalized pressure drop characteristic is same among conductors. This is one of evidences that TF conductor is manufactured uniformly.
Ota, Kunio; Abe, Hironobu; Yamaguchi, Takehiro; Kunimaru, Takanori; Ishii, Eiichi; Kurikami, Hiroshi; Tomura, Goji; Shibano, Kazunori; Hama, Katsuhiro; Matsui, Hiroya; et al.
JAEA-Research 2007-044, 434 Pages, 2007/03
The Horonobe URL Project started in 2000. Research and development activities are planned over three phases, that will span a total duration of about 20 years: the 1st surface-based investigarion phase (6 years), the 2nd URL construction phase (8 years) and rhe 3rd operation phase (12 years). Geological, geophysical, geo-mechanical, hydrogeological, and hydro-geochemical investigations have been carried out during the surface-based investigation.
Seno, Shoji; Niizato, Tadafumi; Kurikami, Hiroshi; Yasue, Kenichi; Yabuuchi, Satoshi; Hara, Minoru; Kunimaru, Takanori; Nakayama, Masashi; Funaki, Hironori; Yamaguchi, Takehiro
no journal, ,
We should estimate ten-thousand-year stability of geological environment to meet the geological disposal of high level radioactive waste. Especially groundwater flow plays an important role because it might cause migration of nuclides. Since long term transitions of geology and topography may influence hydrogeological conditions such as hydraulic gradient and hydraulic conductivities, estimations of vertical displacement rate and erosion rate are also important. This report discusses the method to estimate an amount of erosion in the future based on suspended sediment concentration in rivers as an example in Horonobe area, northern part of Hokkaido.
Kunimaru, Takanori; Ota, Kunio; Abe, Hironobu; Yamaguchi, Takehiro; Ishii, Eiichi; Kurikami, Hiroshi; Tomura, Goji; Shibano, Kazunori; Hama, Katsuhiro; Matsui, Hiroya; et al.
no journal, ,
The Horonobe Underground Research Laboratory (URL) Project is being pursued by the Japan Atomic Energy Agency (JAEA) to enhance the reliability of relevant disposal technologies through investigations of the deep geological environment within the host sedimentary formations at Horonobe, northern Hokkaido. The project consists of two major research areas, "Geoscientific Research" and "R&D on Geological Disposal", and proceeds in three overlapping phases, "Phase I: Surface-based investigation", "Phase II: Construction" and "Phase III: Operation", over a period of 20 years. The present report summarises the results of the Phase I geoscientific research carried out from March 2001 to March 2005. Integration of work from different disciplines into a "geosynthesis" ensures that the Phase I goals have been successfully achieved and identifies key issues that need to be addressed in the Phase II/III investigations.
Sanada, Hiroyuki; Hanakawa, Toshiyuki; Ota, Kunio; Abe, Hironobu; Yamaguchi, Takehiro; Kunimaru, Takanori; Ishii, Eiichi; Kurikami, Hiroshi; Tomura, Goji; Shibano, Kazunori; et al.
no journal, ,
no abstracts in English
Obayashi, Hironari; Yamaguchi, Kazushi; Saito, Shigeru; Sugawara, Takanori; Takei, Hayanori; Sasa, Toshinobu
no journal, ,
Maekawa, Fujio; Sasa, Toshinobu; Takei, Hayanori; Saito, Shigeru; Obayashi, Hironari; Yamaguchi, Kazushi; Wan, T.; Tsujimoto, Kazufumi; Nishihara, Kenji; Sugawara, Takanori; et al.
no journal, ,
As one of experimental facilities of J-PARC (Japan Proton Accelerator Research Complex), we have a plan to construct the Transmutation Experimental Facility (TEF). TEF consists of two facilities: the ADS Target Test Facility (TEF-T) and the Transmutation Physics Experimental Facility (TEF-P). TEF-T equips a liquid lead-bismuth spallation target bombarded by a 400 MeV - 250 kW proton beam in which candidate proton beam window materials are to be irradiated. TEF-P equips a critical/subcritical assembly to investigate physical and dynamic properties of the accelerator-driven system by using a low power (10W) proton beam. Uranium, Plutonium and minor actinide fuels are planned to be loaded into the assembly. Recent progress in R&D efforts toward construction of J-PARC TEF will be presented.
Sugawara, Takanori; Yamaguchi, Kazushi; Obayashi, Hironari; Saito, Shigeru; Yoshimoto, Hidemitsu; Sasa, Toshinobu
no journal, ,
JAEA is planning to build a Transmutation Experimental Facility (TEF) for R&D on volume reduction and mitigation of harmfulness of high-level radioactive waste by using an Accelerator-Driven System (ADS). In the ADS Target Test Facility (TEF-T) of the TEF, a liquid lead-bismuth eutectic (LBE) target will be irradiated with a high-power (250 kW) proton beam, and irradiation effects on structural materials will be studied. On the other hand, LBE is corrosive, so it is necessary to control oxygen concentration in LBE adequately to protect structural materials from the corrosion. In order to control the oxygen concentration in LBE, it is required to develop an oxygen sensor to measure the oxygen concentration. JAEA tried to fabricate two-types of oxygen sensors (platinum type and bismuth type). As the result, it was confirmed that output voltage of the platinum type sensors was adequate in a wide temperature range.
小野 高徳; 川崎 浩平; 山口 文吾