Seismic and environmental qualification of the primary protection system for Sizewell `B´

The Sizewell B nuclear power station primary protection system (PPS) is classified as 1E. Safety class 1E defines electric equipment and systems that are essential to emergency reactor shutdown, containment isolation, reactor core cooling and containment and reactor heat removal or otherwise are essential in preventing significant release of radioactive material to the environment. Here, the authors describe how, for qualification of the PPS it was required to demonstrate that the equipment would perform its safety functions during abnormal environment extremes and during and after a safe shutdown earthquake event