Separation of Facility Safety Systems/Components

DOE-HDBK-6004-99

assemblies should meet the requirements set forth in IEEE-317. The assemblies should be inserted

in and bolted to feed-through sleeves welded to the steel liner of the wall of the containment building

and have a double electrical conductor seal. A seal should be provided at the bolted connection to

the feed-through sleeve.

At least four separate electrical penetration areas should be provided to maintain the physical

separation specified in USNRC Regulatory Guide 1.75. Where Safety-class redundant protection

system sensors are located within the containment building, each circuit should be brought to a

penetration area with separation maintained among the redundant circuits.

The electrical penetration assemblies should conform to USNRC Regulator Guide 1.63.

Three basic types of electrical penetrations should be provided:

Type I

Medium voltage power, 15 kV or 5.0 kV

Type II Power and control, 600 volts and below

Type III Instrumentation, thermocouple, coaxial, triaxial, and other special circuits

Circuit loading should be limited, based upon the manufacturer's recommendations, to ensure that the

temperature will not cause excessive drying of the concrete adjacent to the penetration assemblies.

Provisions should be made for periodic leak testing of the electrical penetration assemblies.

Separation of Facility Safety Systems/Components

Physical separation and independence of electrical systems should be established in accordance with

IEEE-384, Standard Criteria for Independence of Class 1E Equipment and Circuits, and USNRC

Regulatory Guide 1.75 to ensure meeting the requirements of IEEE-308 and 603.

Separation requirements should be applied to the following electrical systems when these systems

serve safety functions:

Cable tray and conduit system

Circuit wiring

Diesel generator or alternate emergency/back-up power system

Medium and low voltage switchgear

Motor control centers

DC batteries, chargers, and distribution system

Electrical penetrations