Steam generator tube rupture (SGTR) is a design basis accident in Lead-cooled Fast Reactor (LFR). A 1/8 centrosymmetric scale geometric model of ELSY primary system is adopted to build the computational domain. A Eulerian-Lagrangian CFD Discrete Phase Model (DPM) with an appropriate drag coefficient correlation is performed, and a base case of bubble transport study is analyzed to obtain the distribution of bubbles. Furthermore, the possibility of bubbles entrained to the core is evaluated. Results show that bubbles firstly reach the core edge channels and then to the middle channels. Meanwhile, a rupture at low and peripheral position can inject more bubbles to the core. In addition, 0.3 mm-0.6 mm and 1 mm bubbles have the largest probability to reach the core, considering the amount of bubbles with different sizes. This study is a guiding paper for bubble transport in SGTR, and it can provide useful reference for judging the impact of accident.