Document: NUREG-0800
Document ID: 41b2cf88-b6dc-4005-939a-cf3fb1a561d2
Document Type: srp
Title: INADVERTENT DECREASE IN BORON CONCENTRATION IN THE REACTOR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0703/ML070380222.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.6
CFR Part: 
CFR Title: 

Content:
s during the life of the nuclear power unit) without other concurrent failures or incidents, regulatory requirements for AOOs apply to their analyses or evaluations. Uncertainties of quantification or measurement of relevant boron dilution event parameters are verified by analyses including appropriate design margins. Thus, GDC 10 assures that analyses demonstrate, under all operating, shutdown, and refueling modes, whether the reactor core and its coolant, control, and protection systems are designed with sufficient margins for postulated boron dilution events to maintain fuel cladding integrity. 2. GDC 13 requires the provision of instrumentation that is capable of monitoring variables and systems over their anticipated ranges to assure adequate safety, and of controls that can maintain these variables and systems within prescribed operating ranges. 15.4.6-6 Revision 2 - March 2007 GDC 13 applies to this section because the reviewer evaluates the sequence of events, incuding automatic actuations of protection systems, and manual actions, and determines whether the sequence of events is justified, based upon the expected values of the relevant monitored parameters and instrumental indicators. 3. GDC 15 requires design of the RCS and its auxiliary, control, and protection systems with sufficient margin so RCPB design conditions are not exceeded during any normal operation, including AOOs. Design conditions (e.g., pressure limits for transients) of the RCPB are established to assure its integrity. The RCPB provides a FP barrier, confined volume for the inventory of reactor coolant, and flow paths for core cooling. In PWRs, boron is added to the reactor coolant in sufficient concentrations for reactivity control. PWR conditions of normal operation include startup, power operation, hot standby, shutdown (hot and cold), and refueling modes. Because of the frequency of boron dilution events (one or more times during the life of the nuclear power unit) without other