Document: NUREG-0800
Document ID: 16650158-402d-4897-850a-bc9e2cce7648
Document Type: srp
Title: INADVERTENT OPENING OF A PWR PRESSURIZER PRESSURE RELIEF
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070726.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.1
CFR Part: 
CFR Title: 

Content:
the positions of Regulatory Guide 1.105 (Ref. 9), "Instrument Spans and Setpoints for Safety-Related 38 Systems," are used with regard to their impact on the plant response to the type of 39 transient addressed in this SRP section. f. The most limiting plant systems single failure, as defined in the "Definitions and Explanations" of Appendix A to 10 CFR Part 50, shall be identified and assumed in the analysis and shall satisfy the positions of Regulatory Guide 1.53 (Ref. 10).40 The applicant's analysis of this transient should be performed using an acceptable analytical model. If the applicant proposes to use other analytical methods, which have not been previously reviewed and approved by the staff, these methods are evaluated by the staff for acceptability. For new generic methods, the reviewer initiates an evaluation of the new analytical model. 15.6.1-5 DRAFT Rev. 2 - April 1996 The values of the parameters used in the analytical model are to 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. 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, axial power profile, and radial power distribution. d. Mitigating systems should be assumed to be actuated in the analyses at