The project will develop a co-simulation platform allows studying the interaction between different systems of a power plant, including thermomechanical, internal electrical and automation system, and off-site transmission power system. Using this co-simulation platform, the project will study safety design principles of electrical systems focusing on selected topics considered most relevant for the stakeholders on the three levels of design: 1) plant level safety design, 2) systems safety design and 3) component safety design. The objective is to reach a general understanding of the set of electrical system initiating events that should be included in a safety case for a nuclear power plant. This includes identifying, classification and simulation of types of plant external and internal events related to electrical systems. Another relevant issue at plant level is to analyse how well redundancy, diversity and separation principles are actually accomplished for electric systems.