Document: NUREG-0800
Document ID: a7fafe76-5570-446b-96dd-3e53ec9bccb3
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340663.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4
CFR Part: 
CFR Title: 

Content:
eactivity," and is considered to be satisfied in light water reactors by the existence of the Doppler and negative power coefficients. There are no criteria that explicitly establish acceptable ranges of coefficient values or preclude the acceptability of a positive moderator temperature coefficient such as may exist in pressurized water reactors at beginning of core life. The acceptability of the coefficients in a particular case is determined in the reviews of the analyses in which they are used, e.g., control requirement analyses, stability analyses, and transient and accident analyses. The use of spatial effects such as weighting approximations as appropriate for individual transients are included in the analysis reviews. The judgment to be made under this SRP section is whether the reactivity coefficients have been assigned suitably conservative values by the appli- cant. The basis for that judgment includes the use to be made of a coef- ficient, i.e., the analyses in which it is important; the state of the 4.3-6 Rev. 2 - July 1981 art for calculation of the coefficient; the uncertainty associated with such calculations; experimental checks of the coefficient in operating reactors; and any required checks of the coefficient in the startup program of the reactor under review. 3. Acceptance criteria relative to control rod patterns and reactivity worths include: a. The predicted control rod worths and reactivity insertion rates must be reasonable bounds to values that may occur in the reactor. These values are used in the transient and accident analyses and judgment as to the adequacy 6f the uncertainty allowances are made in the. review of the transient and accident analyses. b. Equipment, operating limits, and procedures necessary to restrict potential rod worths or reactivity insertion rates should be shown to be capable of performing these functions. It is a CPB position to require, where feasible, an alarm when any limit or restriction is violated or is