IEEE 649-1991 (R2005) pdf free.IEEE Standard for Qualifying Class 1E Motor Control Centers for Nuclear Power Generating Stations.
IEEE 649 An environment expected as the result of the postulated service conditions appropriate for the design basis and postdesign basis accidents of the station.’ Harshenvironments are the result of a loss of coolant accident (LOCA)/high energy line break(HELB) inside containment and HELB or post-LOCA conditions outside containment (seeIEEE Std 323-1983[6].)
mild environment.An environment expected as a result of normal service conditions andextremes (abnormal) in service conditions where seismic motion is the only design basis event(DBE) of consequence (see IEEE Std 323-1983[6].)
motor control center: A floormounted assembly of one or more enclosed vertical sectionshaving a common horizontal power bus and principally containing combination motor starterunits. These units are mounted one above the other in the vertical sections.The sections mayincorporate vertical buses connected to the common power bus, thus extending the commonpower supply to the individual units. Units may also connect directly to the common powerbus by suitable connections.
significant aging mechanism.An aging mechanism is significant if, in the normal andabnormal service environment, it causes degradation during the installed life of the equipment that progressively and appreciably renders the equipment vulnerable to failure to per-form its safety function(s) under DBE conditions.
unit. One independent portion of a motor control center vertical section. It is normally a plugin module that connects to the motor control center vertical bus. vertical section. A portion of the motor control center normally containing one vertical busassembly.
The manufacturers and users of Class 1E motor control centers are required to provideassurance that such equipment can meet or exceed its specific performance requirementsthroughout its installed life. This is accomplished through a quality assurance program thatincludes, but is not limited to, design, qualification, production quality control, installation,maintenance, surveillance, and periodic testing. This document treats only the qualificationportion of the program.
The purpose of the qualification program is to provide assurance that the motor control center is capable of performing its required safety functions with no failure mechanism that couldlead to common cause failures under the postulated service conditions specified in the equipment specification.
Qualification may be accomplished by testing, analysis,operating experience, or a combina-tion thereof. This standard provides qualification methods for each of these alternatives. Withall qualification methods, the end result is the documented evidence that the motor controlcenter is capable of performing its required function(s).
Note that the demonstration of the equipment’s ability to perform required safety functionsin accordance with this standard does not constitute a complete design verification of theequipment being qualified.Rather, it supports the overall design verification process onlywith respect to operation under postulated environmental and service conditions.IEEE 649 pdf download.