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5 results on '"Hiroaki Okitsu"'

1. Overall Hydrogen Permeation through Fluidized PbLi Alloy under Natural Convection

Author

Satoshi Fukada, Hiroaki Okitsu, Shunsuke Yoshimura, Makoto Okada, and Yuki Edao

Subjects
Nuclear and High Energy Physics, Materials science, Natural convection, 020209 energy, Mechanical Engineering, Alloy, 02 engineering and technology, engineering.material, 01 natural sciences, 010305 fluids & plasmas, Physics::Fluid Dynamics, Nuclear Energy and Engineering, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, engineering, Astrophysics::Solar and Stellar Astrophysics, General Materials Science, Tube (fluid conveyance), Composite material, Civil and Structural Engineering, Hydrogen permeation, Eutectic system
Abstract

Hydrogen permeation is investigated in a conjugated system of Li15.8Pb84.2 eutectic alloy or Ar under natural convection inside a cylindrical vertical sus316 tube. Two different temperature conditi...

Published
2013

2. Analysis of diffusion and dissolution of two-component hydrogen (H+D) in lead lithium

Author

Yuki Edao, Satoshi Fukada, Makoto Okada, and Hiroaki Okitsu

Subjects
Materials science, Hydrogen, Mechanical Engineering, Diffusion, Analytical chemistry, chemistry.chemical_element, Blanket, Permeation, Thermal diffusivity, Nuclear Energy and Engineering, chemistry, General Materials Science, Lithium, Dissolution, Civil and Structural Engineering, Eutectic system
Abstract

A lead–lithium eutectic alloy (Pb–Li) is one of the most promising candidate materials for the liquid blanket of an advanced fusion reactor. We have experimentally determined mass-transfer properties by an unsteady permeation method, which data are necessary to design a system to recover tritium (T) from a Pb–Li blanket. An experiment of simultaneous H and D permeation through Li17Pb83 is performed to clarify interactions between atoms in the two-component permeation process. The experimental results are analyzed by a model of one-dimensional or two-dimensional permeation through Li17Pb83. The major permeation proceeds in the longitudinal direction of the present system, and the ratio of hydrogen leak in the radial direction is evaluated using the simulation. As a result, it was found that H and D atoms permeate independently regardless of the H/D component ratio within the present experimental conditions. The permeability and diffusivity of H are 1.4 times higher than that of D. The solubility of H is close to that of D. The isotope effect in diffusivity is in proportion to the square root of the mass ratio of D to H. When these data can be extended to the case of T, T permeability and diffusivity is predicted as 1/1.7 times lower than that of H in the temperature range from 773 K to 973 K.

Published
2012

3. Tritium Recovery from Liquid Blanket Systems for Fusion Reactor

Author

K. Tamari, Makoto Okada, Satoshi Fukada, Kenichi Katekari, Yuki Edao, Yusuke Hatachi, and Hiroaki Okitsu

Subjects
Nuclear and High Energy Physics, Fusion, Materials science, 020209 energy, Mechanical Engineering, Nuclear engineering, FLiBe, 02 engineering and technology, Fusion power, Blanket, 01 natural sciences, 010305 fluids & plasmas, chemistry.chemical_compound, Nuclear Energy and Engineering, chemistry, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Tritium, Civil and Structural Engineering
Abstract

Systems to recover tritium (T) from fusion liquid blankets of LiPb (Li17Pb83) and Flibe (Li2BeF4) under safety conditions are discussed based on available data of T transport properties. We recentl...

Published
2012

4. Permeation of Two-Component Hydrogen Isotopes in Lithium-Lead Eutectic Alloy

Author

Satoshi Fukada, Hiroaki Okitsu, Hidetaka Noguchi, and Yuki Edao

Subjects
Nuclear and High Energy Physics, Materials science, Hydrogen, Isotope, Component (thermodynamics), 020209 energy, Mechanical Engineering, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, Permeation, 01 natural sciences, 010305 fluids & plasmas, Nuclear Energy and Engineering, chemistry, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, General Materials Science, Lithium, Civil and Structural Engineering, Eutectic system
Abstract

We performed an experiment of H and D permeation through Li17Pb83 in the two-component (H+D) system by an unsteady permeation method to clarify interactions between H and D atoms. It was found that...

Published
2011

5. Analysis of Simultaneous H and D Permeation through Lithium-Lead

Author

Yuki Edao, Satoshi Fukada, Hiroaki Okitsu, and Makoto Okada

Subjects
Materials science, chemistry, Saddle point, Kinetic isotope effect, Analytical chemistry, chemistry.chemical_element, Nuclear fusion, Lithium, Fusion power, Permeation, Absorption (chemistry), Condensed Matter Physics, Thermal diffusivity
Abstract

Clarification of tritium transfer in blanket is an important issue for realizing fusion reactor. We perform an experiment of simultaneous H and D permeation through Li17Pb83 by means of an unsteady permeation method in order to clarify the interactions and isotope effects between H and D atoms. The experiment is conducted under the condition where the Sieverts’ law holds. As a result, it is found that (i) H and D atoms permeate independently regardless of the H/D component ratio in the upstream gas and (ii) diffusion process is the rate-determining step in the overall permeation process. The diffusivity of H is around 1.4 times larger than that of D. The solubility of H is close to that of D. We estimate two vibration modes at an absorption site and a saddle point of H in Li17Pb83 based on the ratio of isotope effect. It is considered that the zero-point vibration energy of H at the absorption site in Li17Pb83 is around 0.173 eV and that at the saddle point is around 0.235 eV. The ratio of isotope effect is almost in proportion to the square root of mass ratio of D to H. The diffusivity of T can be estimated as 1/1.7 times of H. c © 2012 The Japan Society of Plasma Science and Nuclear Fusion Research

Published
2012

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