Document: NUREG-0800
Document ID: 94ab38ac-ddfc-4ba1-ae38-bc25ffa6e976
Document Type: srp
Title: – 15.4.5
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070716.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.4.4
CFR Part: 
CFR Title: 

Content:
values of parameters used in the analytical model are to be suitably conservative. The following values are considered acceptable: a. Initial power level is rated output (licensed core thermal power) for the number of loops initially assumed to be operating, plus an allowance of 2% to account for power measurement uncertainty. An analysis to determine the effects of a flow increase must be made for each allowed mode of operation (i.e., one, two, or three loops initially operating) or the effects referenced to a limiting case. b. Conservative scram characteristics are assumed, e.g., maximum time delay with the most reactive rod held out of the core for a PWR and a design conservatism factor of 0.8 times the calculated negative reactivity insertion rate for a BWR. c. The core burnup is selected to yield the most limiting combination of moderator temperature coefficient, void coefficient, Doppler coefficient, axial 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 as determined by ICSBHICB.23 The reviewer shall verify that the protection system (1) initiates automatically the operation of appropriate systems, including the reactivity control systems, to assureensure that specified acceptable fuel design limits are not exceeded for this event and (2) senses the plant conditions and initiates the operation of systems and components important to safety. For BWR plants where flow control is part of the reactivity control system, General Design CriteriaGDC 25, 26, and 28 must be satisfied for this event; otherwise, General Design CriteriaGDC 25, 26, and 28 are not applicable. Where applicable, General Design CriteriaGDC 25, 26, and 28 are satisfied if compliance with General Design CriteriaGDC 10 24 and 15 is demonstrated. Technical Rationale25 The technical rationale for application of these acceptance criteria