Best estimate codes have been used in the past thirty years for the design, licensing and safety of NPP. Nevertheless, strong efforts are necessary for the qualification and the assessment of such codes. The aim of this work is to study the main phenomena involved in the emergency spray cooling injection in a BWR. For this purpose, data from the Swedish separate effect test facility GÖTA have been simulated using TRACE version 5.0 Patch 2. Furthermore, uncertainty calculations have been performed with the PIE method and the identification of the input parameter that mostly influence the code output has been performed.