Document: NUREG-0800
Document ID: b4cff877-ab63-46c3-8140-32e309d767a2
Document Type: srp
Title: EMERGENCY DIESEL ENGINE STARTING SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070571.pdf
Revision Date: 2023-06
Chapter: 9
Section ID: 9.5.6
CFR Part: 
CFR Title: 

Content:
mponents, the EDESS must be designed to perform this safety function in each unit regardless of events, failures, and conditions in DRAFT Rev. 3 - April 1996 9.5.6-6 the other unit(s). Compliance with GDC 5 provides assurance that equipment failures and events occurring in one unit of the site will not propagate to other units of the site. 4. GDC 17, in relevant part, requires provision of an onsite electric power system to permit the functioning of SSC important to safety. GDC 17 requirements include that the onsite electric power system have sufficient independence and redundancy to perform their safety functions assuming a single failure. Typically, the emergency diesel generator system is the onsite electric power system relied upon to meet these requirements. The diesel engine starting system is integral to the emergency diesel generator system. Regulatory Guide 1.9 provides regulatory positions with regard to EDE and starting system design criteria and features applicable to GDC 17 compliance. Meeting the GDC 17 requirements provides assurance that electric power will be available for systems necessary to: 1) prevent fuel damage in the event of anticipated operational occurrences; and 2) maintain core cooling and containment integrity in the event of postulated accidents. 5. 10 CFR 50.63 requires that each light-water-cooled nuclear power plant be able to withstand and recover from a station blackout (i.e., loss of the offsite electric power system concurrent with reactor trip and unavailability of the onsite emergency ac electric power system). Paragraph (a)(2) of 50.63 establishes the conditions under which provision of an alternate ac (AAC) power source will constitute acceptable capability to withstand station blackout. Regulatory Guide 1.155 describes a method acceptable to the NRC staff for complying with 10 CFR 50.63. Plants that have emergency ac sources in excess of minimum redundancy requirements for loss-of-offsite-power conditions may use one of