Document: NUREG-0800
Document ID: 2925ed14-c49b-459b-8786-e6bffd2c43c4
Document Type: srp
Title: AUXILIARY FEEDWATER SYSTEM (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070603.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.9
CFR Part: 
CFR Title: 

Content:
onent failure and fragmentation. In addition to missiles, failure of high energy piping systems, and to a lessor extent moderate energy systems, can result in pipe whip, jet impingement, flooding, and other environmental conditions that can effect the operability of safety-related systems like the AFWS. Compliance with GDC 4 provides assurance that the AFWS will be protected from anticipated environmental conditions and events such that it can support removal of reactor decay heat. 3. GDC 5 prohibits the sharing of SSCs important to safety among nuclear power units unless it can be demonstrated that such sharing will not significantly impair their ability to perform their safety functions including in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units. The AFWS performs the safety function of emergency heat removal from the reactor coolant system and the shutdown and cooldown of the reactor coolant system to low pressure residual heat removal system cut-in conditions. If the AFWS is shared between units, it must be demonstrated that it can accomplish these functions for both units simultaneously. Compliance with GDC 5 DRAFT Rev. 3 - April 1996 10.4.9-8 provides assurance that equipment failures and events occurring in one unit of the site will not propagate to the other units of the site. 4. GDC 19 establishes requirements for design of control room instrumentation and controls for prompt hot shutdown of the reactor and subsequent cold shutdown. Branch Technical Position RSB 5-1 provides guidance for compliance with GDC 19 with regard to achieving cold shutdown from the control room only using safety grade equipment. The AFWS is required for safe shutdown of the reactor during normal and accident conditions, including cooldown of the reactor to the cut-in conditions for low pressure residual heat removal. Compliance with GDC 19 and BTP RSB 5-1 ensures the availability of adequate instrumentation and controls to perform the