Study on a suppression of sodium-water reaction in SFR by applying sodium with suspended nanoparticles

Kanda, Hironori; Yoshioka, Naoki*; Ara, Kuniaki ; Saito, Junichi  ; Nagai, Keiichi 

An important safety concern for SFR is the possibility of steam leaking from a tube at high-pressure into surrounding liquid sodium within the steam generator. The steam/liquid sodium pair is very reactive and the steam leak will form a sodium-water reaction jet which may attack and rupture adjacent tubes. A study on the suppression of the reactivity of sodium itself using the concept of suspended nanoparticles in liquid sodium (sodium nanofluid) has carried out. From the experimental results for sodium nanofluid, it was clear that the reaction rate and reaction heat with water were decreased by the atomic interaction of sodium with suspended nanoparticles. Taking the changes of physical and chemical property into account, an analytical model for peak temperature within a sodium nanofluid-water reaction jet has been constructed. The object of this paper is to confirm this analytical model for reaction jet temperature and to predict a mitigation effect on adjacent tube damage in a steam generator by applying sodium nanofluid to the secondary coolant of SFR. Comparing calculation results using the analytical model with the experimental results for a steam injection experiment, we demonstrated that the analytical model for temperature within the reaction jet is appropriate.