Document: NUREG-0800
Document ID: 25cb3efc-9642-430d-a72f-52decd59b34f
Document Type: srp
Title: INTRODUCTION - TRANSIENT AND ACCIDENT ANALYSES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070710376.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.0
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Content:
REVIEW RESPONSIBILITIES Primary - Organizations responsible for review of transient and accident analyses for PWRs/BWRs Secondary - None The evaluation of the safety of a nuclear power plant requires analyses of the plant’s responses to postulated equipment failures or malfunctions. Such analyses help to determine the limiting conditions for operation, limiting safety system settings, and design specifications for safety-related components and systems to protect public health and safety. These analyses are a focal point of the license amendment request (LAR), design certification (DC), and combined license (COL) reviews. I. AREAS OF REVIEW The specific areas of review are as follows: 1. Categorization of Transients and Accidents. The reviewer ensures that the applicant’s selection and assembly of the plant transient and accident analyses represent a sufficiently broad spectrum of transients and accidents, or initiating events. Initiating events are categorized according to expected frequency of occurrence and by type. Categorization by frequency of occurrence provides a basis for selection of the applicable analysis acceptance criteria for each initiating event. Categorization of 15.0-2 Revision 3 - March 2007 initiating events by type provides a basis for comparison between events, which makes it possible to identify and evaluate the limiting cases (i.e., the cases that can challenge the analysis acceptance criteria). A. Categorization According to Frequency of Occurrence. Each initiating event is categorized as either an anticipated operational occurrence (AOO) or as a postulated accident. AOOs, as defined in Appendix A to 10 CFR Part 50, are those conditions of normal operation that are expected to occur one or more times during the life of the nuclear power unit. The SRP uses the term AOOs to refer to the events that are categorized in Regulatory Guide 1.70 and in Regulatory Guide 1.206 as incidents of moderate frequency (i.e., events that are expected to