The new safety guide on Design of Electrical Power Systems for Nuclear Power Plants (SSG-34) has been recently published. This safety guide provides recommendations on the necessary characteristics of electrical power systems for nuclear power plants, and on the processes for developing these systems, in order to meet the safety requirements of IAEA Safety Standards Series No. SSR-2/1. It reflects the changes that have been made to SSR-2/1, in particular to Requirement 68 on Emergency Power Supply as result of Fukushima accident. This safety guide is a revision of NS-G-1.8 on Design of Emergency Power Systems, issued in 2004, and supersedes it.
The electrical power systems that supply power to systems important to safety are essential to the safety of nuclear power plants. These electrical power systems include both on-site and off-site power systems. The on-site power systems and off-site power systems work together to provide necessary power in all plant conditions so that the plant can be maintained in a safe state. While off-site power systems are not plant equipment, they are, nevertheless, essential to the safety of a nuclear power plant and important to the defence in depth concept. Unlike the previous NS-G-1.8, the SSG-34 addresses the design of the entire plant electrical power systems.