The structural integrity of the y-branch of the embedded steel penstock for the Muju Pumped Storage Power Plant was investigated using the finite element method. The Y-Branch was reinforced by an internal sickle plate. A 3-D Finite element model of the bifurcation was built including the sickle plate and analyzed. A smaller 3-D model of the sickle plate was also built and analyzed. By careful selection of the boundaries for the smaller model the stress output of the smaller model were in good agreement with the results from the comprehensive analysis of the bifurcation. The smaller model provided us with a tool to optimize the shape of the sickle plate, while minimizing the required analytical effort.