Document: NUREG-0800
Document ID: 4b58df3f-1f93-4271-aa73-22de04083915
Document Type: srp
Title: LOSS OF NORMAL FEEDWATER FLOW
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070300709.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.2.7
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Organization responsible for review of transient and accident analyses for PWRs/BWRs Secondary - None I. AREAS OF REVIEW A loss of normal feedwater flow could occur from pump failures, valve malfunctions, or a loss of offsite power (LOOP). The sequence of events for the loss of feedwater transient differs between a boiling water reactor (BWR) and a pressurized water reactor (PWR). A PWR has a backup (auxiliary or emergency) feedwater system while a BWR relies on the emergency core cooling system (ECCS) and reactor core isolation cooling (RCIC) system for backup core cooling. In either case, loss of feedwater flow results in an increase in reactor coolant temperature and pressure which eventually requires a reactor trip to prevent fuel damage. Each event covered in this Standard Review Plan (SRP) section should be discussed in individual sections of the Safety Analysis Report (SAR) or the Design Control Document (DCD), as specified in Regulatory Guide 1.70 and Regulatory Guide 1.206, “Combined License Applications for Nuclear Power Plants (LWR Edition).” For both PWRs and BWRs, fission product decay heat must be transferred from the reactor coolant system following a loss of normal feedwater flow. This can be accomplished by actuation of one or several of the following systems: steam relief system, steam bypass to the 15.2.7-2 Revision 2 - March 2007 condenser, reactor core isolation cooling system (BWR), isolation condenser system (ESBWR), emergency core cooling system (BWR) and auxiliary or emergency feedwater system (PWR). The specific areas of review are as follows: 1. the sequence of events, 2. the analytical model, 3. the values of parameters used in the analytical model, and 4. the predicted consequences of the transient. The sequence of events described in the applicant's SAR or DCD is reviewed by both the organization responsible for reactor systems and the organization for the instrumentation and control systems. The