IEEE 308:1991

Revision Standard - Superseded.
Class 1E portions of ac and dc power systems and instrumentation and control power systems in single-unit and multiunit nuclear power generating stations are covered. Not included are the preferred power supply; unit generator(s) and their buses; generator breaker; step-up, auxiliary, and start-up transformers; connections to the station switchyard; switchyard; transmission lines; and the transmission network. The intent is to provide criteria for the determination of Class 1E power system design features, criteria for sharing Class 1E power systems in multiunit stations, and the requirements for their testing and surveillance.

This standard applies to the Class 1E portions of the following systems and equipment in single unit and multiunit
nuclear power generating stations:
1) Alternating current power systems
2) Direct current power systems
3) Instrumentation and control power systems
These systems include those items listed in Table 1.
The purpose of this standard is to provide the following:1) The principal design criteria and the design features of the Class 1E power systems that enable the systems to meet their functional requirements under the conditions produced by the applicable design basis events.; 2) The requirements for tests and surveillance of the Class 1E power systems.; 3) The criteria for sharing Class 1E power systems in multiunit stations.