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:
plicable) support conclusions of the following type to be included in the staff's safety evaluation report. The reviewer also states the bases for those conclusions. Various operator errors and system malfunctions that could lead to an inadvertent boron dilution incident have been reviewed. Operator errors and system malfunctions that allow the operator the shortest time for corrective action have been analyzed from plant conditions of startup, power operation (automatic and manual), hot standby, hot shutdown, cold shutdown, and refueling. The applicant evaluated these events using a mathematical model previously reviewed and found suitably conservative. Results of the analyses showed that the operator has minutes to take corrective action if a boron dilution incident occurs during refueling and minutes if at-power operation (automatic and manual), startup, hot standby, hot shutdown, and cold shutdown. In the latter case, the most severe transient results in a minimum DNBR of and reactor coolant and main steam system pressures of less than 110 percent of design. The staff concludes that analysis for the decrease in the reactor coolant boron concentration event is acceptable and meets GDCs 10, 13, 15, and 26 requirements. This conclusion is based on the following findings: 1. The applicant meets GDC 10 requirements by demonstrating that the specified acceptable fuel design limits are not exceeded for this event. This requirement is met as the results of the analysis show that the thermal margin limits (minimum DNBR for PWRs) are satisfied as indicated by SER Section 4.4. 2. The applicant meets GDC 13 requirements by demonstrating that all credited instrumentation was available, and that actuations of protection systems, automatic and manual, occurred at values of monitored parameters that were within the instruments’ prescribed operating ranges. 3. The applicant meets GDC 15 requirements by demonstrating whether the RCPB limits are not exceeded for this event. This