Document: NUREG-0800
Document ID: 050fa52d-0a13-4146-93e4-0f4659c7d893
Document Type: srp
Title: LOSS OF NONEMERGENCY AC POWER TO THE STATION AUXILIARIES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350140.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.2.6
CFR Part: 
CFR Title: 

Content:
s and shall satisfy the positions of Regulatory Guide 1.53 (Ref. 14). The applicant's analysis of the loss.of ac power transient should be based on an acceptable model. Models which have been approved by the NRC are identified in References 2 through 8. If the applicant proposes analytical methods which have "The term "moderate frequency" is used in this SRP section in the same sense as in the definitions of design and plant process conditions in References 9 and 10. 15.2.6-3 Rev; 1 - July 1981 not been approved, these are evaluated by the staff for acceptability. For new generic methods, the reviewer requests an evaluation by the appropriate branch. The value of parameters used in the analytical model should be suitably conserv- ative. The following values are considered acceptable for use in the model. a. The initial power level is taken as the licensed core thermal power for the number of loops initially assumed to be operating plus an allowance of 2% to account for power measurement uncertainties, unless a lower power level can be justified by the applicant. *The. number of loops operating at the initiation of the event should correspond to the operating condition which maximizes the consequences of the event. b. Conservative scram characteristics are assumed, i.e., for a PWR - maximum time delay with the most reactive rod held out of the core, and for a. BWR - a design conservatism factor of 0.8 times the calculated negative reactivity insertion rate. c. The core burnup is selected to yield the most limiting combination of moderator temperature coefficient, void coefficient, Doppler coefficient, power profile and radial power distribution. d. Mitigating systems should be assumed to be actuated in the analyses at setpoints with allowance for instrument inaccuracy in accordance wih Regulatory Guide 1.105. Compliance with Regulatory Guide 1.105 is determined by ICSB. III. REVIEW PROCEDURES The procedures below are used during the review of both construction permit