Document: NUREG-0800
Document ID: 94ab38ac-ddfc-4ba1-ae38-bc25ffa6e976
Document Type: srp
Title: – 15.4.5
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070716.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.4
CFR Part: 
CFR Title: 

Content:
STARTUP OF AN INACTIVE LOOP OR RECIRCULATION LOOP AT AN INCORRECT TEMPERATURE, AND FLOW CONTROLLER MALFUNCTION CAUSING AN INCREASE IN BWR CORE FLOW RATE REVIEW RESPONSIBILITIES Primary - Reactor Systems Branch (SRXB)1 Secondary - None I. AREAS OF REVIEW A number of transientsanticipated operational occurrences (AOOs) that may occur with 2 moderate frequency cause either increased core flow or introduction of cooler or de-borated water into the core. These transientsAOOs result in an increase in core reactivity due to decreased moderator temperature, moderator boron concentration, or core void fraction. This 1 Standard Review Plan (SRP) section is intended to be applicable to all such transientsAOOs. 3 Each of these transientsAOOs should be discussed in individual sections of the applicant's safety analysis report (SAR), as required by Regulatory Guide 1.70, "Standard Format and Content of Safety Analysis Reports for Nuclear Power Plants." the Standard Format (Reference 1).4 DRAFT Rev. 2 - April 1996 15.4.4-2 The specific transientsAOOs (Table 15-1, "Representative Initiating Events to be Analyzed in Sections 15.X.X of the SAR," of Reference 1in Regulatory Guide 1.70 ) evaluated are: 5 6 1. Boiling water reactor (BWR): startup of an idle recirculation pump. 2. BWR: flow controller malfunction causing increased recirculation flow. 3. Pressurized water reactor (PWR) with loop isolation valves: startup of a pump in an initially isolated inactive reactor coolant loop where the rate of flow increase is limited by the rate at which the isolation valves open. 4. PWR without loop isolation valves: startup of a pump in an inactive loop. The review of the core flow increase transientsAOOs considers the sequence of events, the analytical model, the values of parameters used in the analytical model, and the predicted consequences of the transientsAOOs. The RSBSRXB reviewer concentrates on the need for the 7 reactor protection system and operator action to secure and maintain the