Numerical visualization on melting and solidification of micron-sized metallic particles by laser irradiation

Takase, Kazuyuki; Muramatsu, Toshiharu; Shobu, Takahisa  

At the commercial use stage in sodium-cooled fast reactors, a securing maintenance and repair more than the equal to that of present water-cooled reactors are requested. Especially, establishment of the repair technology that secures the plant integrity for long-term operation period becomes indispensable in the heat transfer tubes of the steam generator that forms the boundary of sodium and water coolants. Then, as aiming at the standardization of a fiber laser welding technology, an analytical study was begun to simulate numerically the laser welding characteristics of the micron-sized metallic particles on the stainless steel plate. The metallic particle is heated by the laser irradiation and then melts exceeding the melting temperature. From the present result, it was found that a prediction of the liquid metal thermal-hydraulics is possible and the present numerical approach is effective for the optimization of the laser welding method.