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
CFR Part: 
CFR Title: 

Content:
ense applications submitted by applicants pursuant to 10 CFR Part 50 or 10 CFR Part 52. Except when the applicant proposes an acceptable alternative method for complying with specified portions of the Commission’s regulations, the staff will use the method described herein to evaluate conformance with Commission regulations. The provisions of this SRP section apply to reviews of applications submitted six months or more after the date of issuance of this SRP section. The referenced regulatory guides contain implementation schedules for conformance to parts of the method discussed here. 15.0-14 Revision 3 - March 2007 VI. DEFINITIONS Term Definition anticipated operational occurrences (AOOs) Conditions of normal operation that are expected to occur one or more times during the life of the nuclear power unit and include but are not limited to loss of power to all recirculation pumps, tripping of the turbine generator set, isolation of the main condenser, and loss of all offsite power. AOOs are also known as Condition II and III events. anticipated transient without scram (ATWS) AOO followed by the failure of the reactor trip portion of the protection system specified in GDC 20, because of common-mode failure. common-mode failure The result of an event which, because of dependencies, causes a coincidence of failure states of components in two or more separate channels of a redundancy system, leading to the failure of the defined system to perform its intended function. critical power ratio (CPR) That power in the assembly that will cause some point in the assembly to experience boiling transition, divided by the actual assembly operating power. departure from nucleate boiling (DNB) The DNB acceptance criterion for an AOO is met when there is a 95 percent probability at a 95 percent confidence level (the 95/95 DNB criterion) that DNB will not occur, and the fuel centerline temperature stays below the melting temperature. design basis Information that identifies the