Document: NUREG-0800
Document ID: d4441736-a9bb-45c2-8d16-d23e8312ab08
Document Type: srp
Title: CHEMICAL AND VOLUME CONTROL SYSTEM MALFUNCTION THAT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070717.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.6
CFR Part: 
CFR Title: 

Content:
d refueling modes. Because of the frequency with which boron dilution events are anticipated to occur (one or more times during the life of the nuclear power unit) without other concurrent failures or incidents, regulatory requirements associated with anticipated operational occurrences are applied to their analyses/evaluation. Reactor coolant system pressure transients attendant to power increases resulting from postulated boron dilution events are analyzed to demonstrate that pressure limiting design features, including conservatively assumed responses of control and protection systems, will maintain pressures below the RCPB design pressure limits for transients. Inherent uncertainties associated with quantification or measurement of relevant boron dilution event parameters are verified by the analyses to be addressed through inclusion of appropriate design margins. Application of GDC 15 thus assures that analyses demonstrate, under conditions of normal operation, including the effects of postulated boron dilution events, that the reactor coolant system and associated auxiliary, control, and protection systems are designed with sufficient margin so that the integrity of the RCPB will be maintained. 3. GDC 26 requires that the control rods be capable of reliably controlling reactivity changes to assure that under conditions of normal operation, including anticipated operational occurrences, and with appropriate margin for malfunctions such as stuck rods, specified acceptable fuel design limits are not exceeded. Fuel design limits are established to assure the integrity of fuel cladding as a fission product barrier. In PWRs, a control rod system is provided for reactivity control. Boron is also added to the reactor coolant in sufficient concentrations to effect reactivity control. PWR conditions of normal operation include startup, power operation, hot standby, shutdown (hot and cold), and refueling modes. The control rods may reduce reactivity only when withdrawn