Survey of Robustness Measures in Electrical Designs in Nuclear Power Plants

The electrical connection of the different nuclear power plants in Finland and Sweden has been reviewed in terms of their single line diagrams and how they are connected to the grid.

A nuclear power plant needs a stable power supply during both normal and abnormal conditions, both to maintain an acceptable nuclear safety and to support the transmission system to maintain a high electrical quality and its ability to deliver power to customers. There are different solutions to obtain a design that is reliable and robust enough to fulfil such function in an acceptable way. The aim of the this research project has been to document different design options for electrical power systems in nuclear power plants, including the option to use alternative sources of energy to achieve the intended function. 

Means of diversifying the connection to the grid using other connections, such as cross-coupling, connection to both off-site switchgears etc. has been discussed showing some possible ways of increasing robustness by means of not connecting all electrical trains to the same source.

Motor generating sets, MG-sets, as a mean of isolating the electrical system of the plant from the off-site power system has been identified as a good measure and no common cause failures have been identified. Read the report.