This paper provides a comprehensive overview of Tractebel’s current capabilities in transient simulation of Pressurized Water Reactors (PWRs) using multi-physics approaches. It highlights the use of advanced, industry-grade simulation tools and methodologies to tackle practical engineering and licensing studies for PWRs. The paper first introduces the dedicated coupling environment and its recent advancements, which have culminated in the CERES Multiphysics platform. It then delves into three key safety application areas where Tractebel’s multi-physics simulation capabilities are applied, with a focus on system transient analysis:•Small Modular Reactor (SMR) R&D Activities: Tractebel’s contribution to the Horizon 2020 McSAFER project is discussed.•Plant Safety Analyses: The paper discusses studies conducted within the framework of the WENRA RL DEC-A safety analyses.•Plant Operational Support: The paper details how multi-physics simulations are used to justify plant restarts after outages as a preventive measure against potential technical specification violations.The paper also outlines future developments aimed at enhancing and applying these multi-physics simulation capabilities to support new plant designs, including SMRs.