White paper: Grid code and nuclear safety

The impact of grid code requirements to the design of nuclear power plants with the focus on the nuclear island and the design of the safety systems is described. Grid reliability, voltage and frequency variations are the main aspects to be considered. Nuclear power plants depend heavily on the grid availability and its quality of voltage and frequency. Changes in grid behavior as a consequence of e.g. deregulation of the market, introduction of renewable power production with high variation in production (like wind and solar) and higher utilization of the grid could have an impact on the nuclear safety, especially if older plants (some are in operation for more than 40 years) have not been designed for these conditions.