Document: NUREG-0800
Document ID: e75b7685-2a36-4e9b-a431-02d166dcf372
Document Type: srp
Title: LOSS OF NONEMERGENCY AC POWER TO THE STATION AUXILIARIES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070681.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.2.6
CFR Part: 
CFR Title: 

Content:
are acceptable computer codes for non-LOCA transient analysis for CE80+ applications. References 24 and 25 are acceptable transient analysis computer codes 38 for Advanced Boiling Water Reactor (ABWR) applications. If the applicant proposes 39 analytical methods which have 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 conservative. 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. 15.2.6-5 DRAFT Rev. 2 - April 1996 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 with Regulatory Guide 1.105. Compliance with Regulatory Guide 1.105 is determined by ICSBHICB.40 Technical Rationale The technical rationale for application of these acceptance criteria to reviewing the loss of nonemergency ac power to the station auxiliaries is discussed in the following paragraphs:41 (a) Compliance with GDC 10 requires that the reactor core and associated