M. Nagai, K. Fukunaga, H. Sato, K. Nagai, J. Saito, K. Ara
Mitsubishi Heavy Industries, Ltd.,
Keywords: nanofluid, fast breeder reactor, coolant, liquid sodium, nanoparticle, chemical reactivity, Titanium
Summary:Although liquid sodium has an excellent thermal property as a coolant of the fast breeder reactor, it has disadvantage due to the high chemical reactivity with water and oxygen. The authors reported in a previous paper that the atomic interaction between sodium and nanoparticles increases and has the potential to suppress chemical reactivity. In this article, the development study of the fabrication technology of nanofluid which is the dispersion of the nanoparticle in sodium to reduce the chemical activity of sodium will be reported. Reduction of the chemical activity of nanofluid is seemed to be caused by interaction between the atom at the surface of nanoparticle and liquid sodium atom. In order to produce proper nanofluids, nanoparticles must have a clean surface. And its particle size should be about 10-50nm. This study used a gas-phase evaporation and condensation method for fabrication of nanoparticles because this method can make the nanoparticles having clean surfaces. Titanium(Ti) was used as nanoparticle material because of its stability in Liquid Sodium. The main factors to control the nanoparticle size are vapor cooling rate and vapor concentration. In this study, these factors were evaluated using the data of particle size distribution from the TEM observation result. And proper condition of these factors to control the particle size were investigated.