Document: NUREG-0800
Document ID: a2d035da-992b-42e8-894f-787a019b437d
Document Type: srp
Title: NUCLEAR DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070410.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.3
CFR Part: 
CFR Title: 

Content:
cceptable fuel design limits be specified that are not to be exceeded during normal operation, including the effects of anticipated operational occurrences. The reactor core's nuclear design is one of several key design aspects that ensure fuel design limits will not be exceeded during normal operations. Compliance with GDC 10 significantly reduces the likelihood of fuel failures occurring during normal operations, including anticipated operational occurrences, thereby minimizing the possible release of fission products to the environment. 2. GDC 11 requires that the net effect of prompt inherent nuclear feedback characteristics in the core tend to compensate for rapid increases in reactivity when operating in the power range. The nuclear design of the reactor core establishes the various reactivity coefficient values which produce the desired feedback characteristics. Compliance with GDC 11 causes the reactor core to be inherently safe during power range operations, thus eliminating the possibility of an uncontrolled nuclear excursion. 3. GDC 12 requires that the reactor core and the associated coolant, control, and protection systems be designed to ensure that power oscillations which result in conditions exceeding specified acceptable fuel design limits are not possible, or can be reliably and readily detected and suppressed. Power oscillations within the reactor core may result from conditions such as improper fuel design or loading, or improper reactivity control including control rod positioning, coolant flow instabilities, moderator void formation, and instabilities associated with nonhomogeneous reactor coolant density distributions. 4.3-9 DRAFT Rev. 3 - April 1996 The occurrence of power oscillations can lead to excessive localized power peaking or cyclic thermal fatigue, and may cause fuel design limits to be exceeded. Compliance with GDC 12 provides assurance that the nuclear design of the reactor core will prevent power oscillations that could challenge