Materials Design Division

Nuclear Materials Engineering

Ryuta KASADA

Prof.Ryuta KASADA

  • Assist. Prof. Yoshitaka MATSUKAWA
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Materials resistant to extreme environments open the door to the next generation base load power plants

High-temperatures in furnace, low-temperatures at Antarctica, vacuum and radiation in space, high pressure under the deep sea..., these are distinguished extreme environments that cannot be tolerated by living human beings. Human beings have made it possible to explore and utilize these extreme environments by creating new materials resistant to the extreme conditions that will serve as barriers to separate the extreme environments from human activities. It is not exaggeration to say that the extreme environment is exactly the frontier of humankind and the invention of extreme environment resistant materials has led the development of human civilization.
One of the frontiers of living human beings is the development of new energy sources. Various unutilized energy sources have been proposed so far, and among them, "fusion reactor" is expected as a base load energy source supporting human civilization for a long time. However, complex extreme environment in the nuclear fusion reactor which overlaps with high temperature, high pressure, and radiation is a barrier to its realization. Our laboratory is pursuing research and development on materials resistant to extreme environments that are key to the realization of next generation energy sources such as fusion reactors or advanced fission nuclear power systems.

Irradiation effects, nanoparticle-dispersion strengthened materials, nanoindentation, environmental effects, coating
Helium cavity trapped by interface between nano-oxide particles

Helium cavity trapped by interface between nano-oxide particles and matrix

 

Create materials resistant to extreme conditions

Our laboratory is developing "nano-oxide particle dispersion strengthened (ODS) alloy" which exhibits superior performance against high temperature and radiation, especially as a material to be used in fusion reactors. Nano-ODS alloys exhibit excellent properties by forming a microstructure in which nano-size oxide particles are dispersed densely in a metal matrix. However, in order to obtain such a fine microstructure, it is impossible to apply the conventional melting method which is the usual process for producing metallic materials. We have succeeded in enhancing the irradiation resistance of ODS alloys by controlling the microstructure to disperse nano-oxide particles at high density.

High-temperature steam environment

High-temperature steam environment

 

 

Evaluate the materials under extreme environments

Our laboratory is able to evaluate the mechanical properties, thermal properties and so on of materials created by using most advanced equipment. We are also developing a new evaluation method especially for nanoindentation in order to investigate the mechanical properties from nanometer to micrometer of materials placed in extreme environments. It is also important to elucidate the function of elements and microstructure which govern material properties and further deterioration. For example, we utilized an electron microscope equipped with a high-resolution soft X-ray spectroscope capable of simultaneous analysis of electronic state and microstructure in order to obtain fundamental knowledge contributing to prediction of debris status at Fukushima Daiichi Nuclear Power Station. Through these studies, we are developing a material engineering basis that can contribute not only to nuclear fusion reactors but also to the safety of nuclear plants.

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