Document: NUREG-0800
Document ID: 0b17303b-e5cc-4091-b22c-056b0c78eb34
Document Type: srp
Title: – 15.3.4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070707.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.3.3
CFR Part: 
CFR Title: 

Content:
gn analysis of the Advanced Boiling Water Reactor (ABWR). References 15 through 35 19 were found to be acceptable computer codes for transient analyses (i.e., except for loss-of- coolant accidents, or LOCAs) for the Combustion Engineering System 80+ final safety evaluation report staff review. In addition, NUREG-1465 contains guidance on accident 36 source terms for light-water nuclear power plants. When conducting transient analyses, the NUREG-1465 guidance is particularly important for reviewing fractions of relevant isotopes (noble gases, iodine, cesium, and rubidium) and chemical species of iodine assumed to exist within the gap between fuel pellets and cladding. If other analytical methods are proposed by 37 the applicant, these methods are evaluated by the staff for acceptability. For new generic methods, the reviewer requests an evaluation. There are certain assumptions regarding important parameters used to describe the initial plant conditions and postulated system failures which should be used. These are listed below: i. 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. ii. 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. iii. 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. Technical Rationale38 The technical rationale for application of these acceptance criteria to