IEEE Std 308-2020 pdf free download – IEEE Standard Criteria for Class 1E Power Systems for Nuclear Power Generating Stations.
4. Principal design criteria
4.1 General Class 1E power systems shall be designed to provide that no design basis event causes the following:
— A loss of electric power to a number of engineered safety features, surveillance devices, or protection system devices so that a required safety function cannot be performed.
— A loss of electric power to equipment that could result in a reactor transient capable of causing signifcant damage to the fuel cladding or to the reactor coolant pressure boundary.
4.2 Relationship between the safety system and Class 1E power system The portions of the Class 1E power system that are required to support safety systems in the performance of their safety functions shall meet the requirements of IEEE Std 603™. Other components, equipment, and systems within Class 1E power systems that have no direct safety function and are provided only to increase the availability or reliability of the Class 1E power system shall meet the requirements in IEEE Std 603 to confrm that these components, equipment, and systems do not degrade the Class 1E power system below an acceptable level.
The safety system criteria that these elements would not have to meet, for example, include the criteria as defned in IEEE Std 603 for operating bypass, maintenance bypass, and bypass indication. An analysis shall be made to confrm that when these components, equipment, or systems are utilized, the consequences of any operation or failure are acceptable to the Class 1E power system.
Components, equipment, or systems required to provide some protective action, such as containment integrity protection, or utilized to provide isolation protection, shall meet the requirements of IEEE Std 603. Figure 1 illustrates the relationship between a typical safety function and the Class 1E power system.
Figure 2 and Figure 3 illustrate a Class 1E power system and its components.
4.3 Design basis event efects
Design basis events established for the unit shall indicate the postulated events that might adversely affect the Class 1E power system. The severity and expected results of those events shall be defned. The required portions of the Class lE power systems shall be capable of performing their function when subjected to the effects of any design basis event.
4.4 Design basis
A specifc design basis shall be provided for the Class 1E power systems of each nuclear power generating station. The design basis shall include, as a minimum, the following:
a) Events requiring the operation of Class 1E power systems
b) Actuation signals for the operation of Class 1E power systems
c) A list of the loads connected to Class 1E buses and standby power supplies
d) The sequence for start-up and the loading profle of Class 1E power sources
e) Time, voltage, speed, and other limits applicable to the standby generators and their prime movers when subjected to the sequence of events in item d)
f) The malfunctions, accidents, environmental events, and operating modes (see Table 1) that could physically damage Class 1E power systems or lead to degradation of system performance and for
which provisions shall be incorporated
g) The acceptable ranges for transient and steady-state conditions of both the energy supply and environment (e.g., voltage, frequency, humidity, temperature, pressure, vibration, etc.) during normal,abnormal, and accident circumstances throughout which the equipment must perform.IEEE Std 308 pdf download.