Advanced Energy Structural Materials Research Section

概要

Materials development and maintenance manage- ment is essential for establishment of the safety and efficient operation of advanced nuclear energy sys- tems. This section addresses the mission of establish- ing a maintenance management methodology as well as material R & D for advanced nuclear energy sys- tems such as fusion and fission reactors. Current main researches are as follows:

(1) Plant integrity analysis: The structural integrity of a reactor pressure vessel (RPV) is important for re- actor safety and was investigated using three-dimen- sional computational fluid dynamics (3D-CFD) and the finite element method (FEM). Pressurized thermal shock (PTS) during emergency water cooling, the most severe situation, was focused in the present study. Through this investigation, the magnitude of the risk of the RPV function loss was evaluated and proposed as an indicator available for optimizing the mainte- nance strategy.

(2) Materials multiscale modeling and data science: Radiation damage processes in nuclear materials take place at a wide variety of time and length scales. So- called the multiscale viewpoint and statistical argu- ments are required to understand the processes. To do this, modeling effort has been made using several computational techniques complementarily such as molecular dynamics, ab-initio quantum calculations, kinetic Monte-Carlo, rate-equation theory analysis, FEM and CFD.

(3) Irradiation effects on microstructure evolution and properties of materials: High energy particle ir- radiation leads to the formation of oversaturated in- terstitials and vacancies. The behavior of point de- fects is responsible for the evolution of the micro- structure, which may cause degradation, (or develop- ment), of the mechanical properties of the material. Hence, the elucidation of the behavior of point defects is essential for understanding the mechanisms respon- sible for the changes in mechanical properties. In our study, the microstructure evolution under high energy particle irradiation has been investigated experimen- tally and computationally.

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