Document: NUREG-0800
Document ID: 2cb61281-91f4-400a-8eda-41e187e51d77
Document Type: srp
Title: AUXILIARY FEEDWATER SYSTEM (PWR)
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070570007.pdf
Revision Date: 2023-06
Chapter: 10
Section ID: 10.4.9
CFR Part: 
CFR Title: 

Content:
supporting systems, align the auxiliary feedwater sources, and open flow paths from the auxiliary feedwater pumps to the steam generator(s). The system is also designed with the capability to manually initiate the necessary protective actions. The AFWS is designed with redundant instrumentation so that the system will automatically limit (may be flow limiting orifice rather than 10.4.9-13 Revision 3 - March 2007 instrumentation) or terminate auxiliary feedwater flow to a depressurized steam generator, and to assure that the minimum required flow is directed to the intact steam generator(s). The electrical portion of this review is performed by the organization responsible for instruments & controls. If a flow limiter is used then it must be demonstrated that sufficient flow still goes to the intact steam generator and containment design pressure is not exceeded by the AFW flow to the depressurized generator. G. The AFWS is designed with sufficient flow capacity so that the system can remove residual heat over the entire range of reactor operation and cool the plant to the decay heat removal system cut-in temperature. This review is performed by the organization(s) responsible for review of reactor systems. H. The AFWS components are designed to function with the anticipated water quality of raw water systems when they are used as the safety-related, seismically qualified source of water. In particular, the design should incorporate provisions for the filtration and removal of particulate debris that could clog components used for throttling of flow. I. The AFWS air-operated safety-related components are designed to perform their safety functions during all design-basis events, including a loss of the normal instrument air system. This design verification should include a review of air-operated component failure positions to verify that they are correct for assuring performance of required safety functions. This issue is described in Generic Letter 88-14,