Hydrogenation of iron in the early stage of Earth's evolution

Iizuka, Riko*; Yagi, Takehiko*; Goto, Hirotada*; Okuchi, Takuo*; Hattori, Takanori; Sano, Asami

Nature Communications (Internet), 8, p.14096_1 - 14096_7, 2017/01

AA2016-0524.pdf:0.73MB

https://doi.org/10.1038/ncomms14096

Density of the Earth's core is lower than that of pure iron and the light element(s) in the core is a long-standing problem. Hydrogen is the most abundant element in the solar system and thus one of the important candidates. However, the dissolution process of hydrogen into iron remained unclear. Here we carry out high-pressure and high-temperature in situ neutron diffraction experiments and clarify that when the mixture of iron and hydrous minerals are heated, iron is hydrogenized soon after the hydrous mineral is dehydrated. This implies that early in the Earth's evolution, as the accumulated primordial material became hotter, the dissolution of hydrogen into iron occurred before any other materials melted. This suggests that hydrogen is likely the first light element dissolved into iron during the Earth's evolution and it may affect the behaviour of the other light elements in the later processes.

Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments

Sano, Asami; Hattori, Takanori; Arima, Hiroshi*; Yamada, Akihiro*; Tabata, Satoshi*; Kondo, Masahiro*; Nakamura, Akihiro*; Kagi, Hiroyuki*; Yagi, Takehiko*

Review of Scientific Instruments, 85(11), p.113905_1 - 113905_8, 2014/11

https://doi.org/10.1063/1.4901095

We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm . Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.

Experimental study on control blade degradation and its modeling

Kurata, Masaki; Shibata, Hiroki; Sakamoto, Kan*; To, Takehiko*

Proceedings of 2014 Water Reactor Fuel Performance Meeting/ Top Fuel / LWR Fuel Performance Meeting (WRFPM 2014) (USB Flash Drive), 8 Pages, 2014/09

Control blade degradation is predicted to occur at the early stage of severe accident of boiling water reactor. Simulation tests and modeling are being performed by collaboration among JAEA, Hitachi-GE Nuclear Energy (Hitachi-GE), Nippon Nuclear Fuel Development (NFD), and Nippon Steel & Sumitomo Metal Corporation (NSSMC). Preliminary simulation tests under inert atmosphere indicated that complicated chemical reactions progressed and that finally the mixture of degraded control blade and the channel box separated into two parts. The first part rich in Zr had low melting temperature and flowed down from the high temperature region like candling. The second part rich in steel, B, and C mechanically collapsed down at temperatures higher than approximately 1673K. The interaction between the control blade and the channel box was highly exothermic. Preliminary model for control blade degradation is being developed using VOFFLUENT, which successfully simulates the early stage ofthe control blade degradation.

Compression behaviors of distorted rutile-type hydrous phases, MOOH (M = Ga, In, Cr) and CrOOD

Sano, Asami; Yagi, Takehiko*; Okada, Taku*; Goto, Hirotada*; Kikegawa, Takumi*

Physics and Chemistry of Minerals, 39(5), p.375 - 383, 2012/05

https://doi.org/10.1007/s00269-012-0487-y

X-ray diffraction measurements of distorted rutile-type oxyhydroxides -GaOOH, InOOH, -CrOOH, and -CrOOD were taken at a maximum pressure of up to 35 GPa under quasi-hydrostatic conditions, at ambient temperature. Anomalies in the evolution of the relative lattice constants and the axial ratios of -GaOOH, InOOH, and -CrOOD suggest anisotropic stiffening along the a- and/or b-axes where the hydrogen bond is formed. The changes were observed at 15 GPa in -GaOOH and InOOH and at 4 GPa in -CrOOD. The pressures were higher in oxyhydroxides that have longer O...O distances of the hydrogen bond at ambient pressure. In contrast, such stiffening behavior was not observed in CrOOH, which has a significant short O...O distance and strong hydrogen bond. The stiffening behaviors observed in the present study can be attributed to the symmetrization of the hydrogen bonds in oxyhydroxides, as was previously found in -AlOOH(D).

Status of Japanese design and validation activities of test facilities in IFMIF/EVEDA

Wakai, Eiichi; Kikuchi, Takayuki; Kogawara, Takafumi; Kimura, Haruyuki; Yokomine, Takehiko*; Kimura, Akihiko*; Nogami, Shuhei*; Kurishita, Hiroaki*; Saito, Masahiro*; Nishimura, Arata*; et al.

Proceedings of 23rd IAEA Fusion Energy Conference (FEC 2010) (CD-ROM), 6 Pages, 2011/03

Japanese activities of test facilities in IFMIF-EVEDA (International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities) project have three subjects of engineering design of post irradiation examination (PIE) facilities, small specimen test technique (SSTT), and engineering design of high flux test module (HFTM), and this paper is summarized about present status. Functional analysis and design of 2-D and 3-D models of PIE facility were performed. In HFTM, as materials of heater, W-3Re alloy and/or SiC/SiC composite were selected in the points of high temperature materials, fabrication technology and some suitable properties such as resistance of thermal shock, high temperature re-crystallization, ductility, resistance of irradiation degradation, and low-activation. In SSTT, a test machine of fracture toughness was designed and developed for small specimens with 10 mm square, and it had high accuracy controllability for stress and displacement.

Superconducting properties of Pr-based filled skutterudite PrRuAs

Namiki, Takahiro*; Aoki, Yuji*; Sato, Hideyuki*; Sekine, Chihiro*; Shirotani, Ichimin*; Matsuda, Tatsuma; Haga, Yoshinori; Yagi, Takehiko*

Journal of the Physical Society of Japan, 76(9), p.093704_1 - 093704_4, 2007/09

https://doi.org/10.1143/JPSJ.76.093704

Laser heated diamond anvil apparatus at the Photon Factory and SPring-8; Problems and improvements

Yagi, Takehiko*; Kondo, Tadashi*; Watanuki, Tetsu; Shimomura, Osamu; Kikegawa, Takumi*

Review of Scientific Instruments, 72(2), p.1293 - 1297, 2001/02

https://doi.org/10.1063/1.1343868

no abstracts in English

Survey and study on examination equipments for in-vessel components inspection in JOYO(II)

*; Sekiguchi, Mineo*; *; *; *

PNC TJ9164 95-012, 50 Pages, 1995/03

PNC-TJ9164-95-012.pdf:1.64MB

As a part of the development of the in-service inspection and repair(ISI & R) technology of FBR, study on examination equipments as visual method to verify in-vessel structures and assemblies was conducted. The objects of the study were higher resolution equipments using ultrasonic transducer technology to examine top area of assemblies in core support structure and parts of the core support structure where entrance nozzles of assemblies were inserted and withdrawn when refueling in 'JOYO'. As the result of the study, basic specification and structures of transducers and signal processing units, and conceptual design of basic structure of drive mechanics for the transducers were derived. The items and plan of the development of the equipments were made.

Treatment of radioactive waste at Japan's Atomic Energy Research Institue

*; ; Ishihara, Takehiko; ;

Disposal of Radioactive Wastes, 1, P. 526, 1960/00

no abstracts in English

A Feasibility study of neutron powder diffraction under high pressure with the Engineering Materials Diffractometer "TAKUMI" at J-PARC

Abe, Jun; Hattori, Takanori; Komatsu, Kazuki*; Arima, Hiroshi; Arakawa, Masashi*; Okuchi, Takuo*; Kagi, Hiroyuki; Yagi, Takehiko*; Uwatoko, Yoshiya*; Matsubayashi, Kazuyuki*; et al.

no journal, , 

We have examined the feasibility of in situ neutron powder diffraction under high pressure with the Engineering Materials Diffractometer "TAKUMI", which has been constructed at BL19 in the Materials and Life Science Facility (MLF) of J-PARC. We have tested two types of high pressure devices at TAKUMI, a Paris-Edinburgh press and a Palm cubic anvil cell. Neutron poder diffraction profiles of Pb placed in the high pressure devices as a standard material were collected. As results, diffraction peaks of Pb were clearly observed. In this study, it has been confirmed that in situ neutron powder diffraction under high pressure can be made with a combination of the high pressure devices and the TAKUMI at J-PARC.