Document: NUREG-0800
Document ID: 2cd63ebf-9196-42c0-880d-a80500b202a4
Document Type: srp
Title: - 15.1.4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550005.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.1.1
CFR Part: 
CFR Title: 

Content:
DECREASE IN FEEDWATER TEMPERATURE, INCREASE IN FEEDWATER FLOW, INCREASE IN STEAM FLOW, AND INADVERTENT OPENING OF A STEAM GENERATOR RELIEF OR SAFETY VALVE REVIEW RESPONSIBILITIES Primary - Organization responsible for the review of transient and accident analyses for PWRs/BWRs Secondary - None I. AREAS OF REVIEW 1. A number of events which are expected to occur with moderate frequency, and which involve an unplanned increase in heat removal by the secondary system, are covered by this Standard Review Plan (SRP) section. Excessive heat removal, i.e., a heat removal rate in excess of the heat generation rate in the core, causes a decrease in moderator temperature which increases core reactivity and can lead to a power level increase and a decrease in shutdown margin. The power level increase will lead to a reactor trip. Any unplanned power level increase may result in fuel damage or excessive reactor system pressure. Each of the initiating events covered by this 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). 15.1.1-15.1.4-2 Revision 2 - March 2007 The specific areas of review are as follows: A. Pressurized Water Reactors (PWRs) i. Feedwater system malfunctions that result in a decrease in feedwater temperature. ii. Feedwater system malfunctions that result in an increase in feedwater flow. iii. Steam pressure regulator malfunctions or failures that result in increased steam flow. iv. Inadvertent opening of a steam generator relief or safety valve. v. For AP1000 plants, Inadvertent actuation of the passive RHR (PRHR). The inadvertent actuation of the PRHR system may be caused by operator action or a false actuation signal that opens the valves that normally isolate the PRHR heat exchanger from the RCS. This moderate-frequency event causes an injection