Document: NUREG-0800
Document ID: 7544d2bf-daeb-45a0-a330-e11124ef4465
Document Type: srp
Title: - 15.3.4-6
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070550012.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.3.3
CFR Part: 
CFR Title: 

Content:
control systems be designed to have a combined capability (in conjunction with poison added by the emergency core cooling system) of reliably controlling reactivity changes, thereby ensuring that the capability for core cooling is maintained under postulated accident conditions and with appropriate margin for stuck rods. Compliance with GDC 28 requires that reactivity control systems be designed with appropriate limits on the amount and rate of reactivity increase, thereby ensuring that the effects of postulated reactivity accidents can neither (a) result in damage to the reactor coolant pressure boundary greater than limited local yielding nor (b) disturb the core, its support structures, or other reactor pressure vessel internals sufficiently to impair the capability to cool the core. Postulated reactivity accidents to be considered shall include rod ejection (unless prevented by positive means), rod dropout, steam line rupture, changes in reactor temperature and pressure, and the addition of cold water. GDC 27 and GDC 28 are applicable to this section because the reviewer evaluates two events (i.e., RCP rotor seizure and shaft break) that will result in transient conditions having the potential to affect reactor coolant temperature and pressure, which in turn could result in complex changes in core reactivity. The applicant's analyses of these transients in the SAR must demonstrate that reactivity, pressure, and temperature changes will not be severe enough to cause an unacceptable impact on the reactor