Power transient boiling has been studied for decades, however, the mechanistic understanding of phenomena which occur during such an event remains incomplete. Due to a dearth of systematic researches, the information of studied phenomenon, detailed physics and applicable hypothesis are very limited. Transient critical heat flux (CHF) is paramount in determining the safe operations of a nuclear reactor. The Transient Reactor Test Loop (TRTL), serves as an out-of-pile facility which supports the testing of conditions experienced in the Transient REActor Test (TREAT) facility at the Idaho National Laboratory (INL). Specifically, the TRTL was designed and operates with the focus on the power transient boiling phenomenon under the Pressurized Water Reactor (PWR) condition. Since the direct application of power transient experiments may lead to a potential safety concern, it is crucial to develop a Computational Fluid Dynamics (CFD) model and simulation method that provides a feasible way to recognize the irregular type of boiling processes that takes place in the TRTL facility and would therefore take place within the TREAT facility as well. With the expensive computational cost and heavy instability from the fast-changing boundary conditions and complicated two-phase physics, the available literature associated with studying transient boiling via CFD is limited. In this study, a new approach is developed with the consideration of heating and temporal behavior. An integral view of the CFD study includes model selection, grid independent study and stability maintenance. To develop a qualitatively confident result from the new approach, a brief data benchmark via available past experimental studies is provided. In addition, a new hypothesis which is able to solve the current debating of the transient boiling phenomenon based on the simulation is discussed as well.