Document: NUREG-0800
Document ID: 4d7d277e-c006-45d6-94df-c84845dd68d0
Document Type: srp
Title: INADVERTENT OPENING OF A PWR PRESSURIZER PRESSURE RELIEF VALVE OR A BWR
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350144.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.1
CFR Part: 
CFR Title: 

Content:
med using an acceptable analyical model. If the applicant proposes to use other analytical methods, which ave 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. MThe term "moderate frequency" is used in this SRP section in the same sense as in the description of design and plant process conditions in References 7 and 8. 15.6.1-3 Rev. 1 - July 1981 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 setpoints with allowance for instrument inaccuracy in accordance with Regulatory Guide 1.105. Compliance with Regulatory Guide 1.105 is determined by ICSB. III. REVIEW PROCEDURES The procedures below are used during both the construction permit (CP) and operating license (OL) reviews. During the CP review, the values of system parameters and setpoints used in the analysis will be preliminary in