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:
d and turbine trip (PWR and BWR) • Control rod drop (inadvertent addition of absorber) (PWR) • Single error of an operator (PWR and BWR) • Single failure of a control component (PWR and BWR) • Single failure in the electrical system (PWR and BWR) • Minor reactor coolant system (RCS) leak or loss of reactor coolant such as from a small ruptured pipe or from a crack in a large pipe (PWR and BWR) • Minor secondary system break (PWR) • Loss of offsite power (PWR and BWR) • Operation with a fuel assembly in an improper position (PWR and BWR) • Inadvertent blowdown of RCS (BWR) • Loss of feedwater heating (PWR and BWR) • Trip of any or all recirculation pumps (BWR) • Inadvertent pump start in a hot recirculation loop (BWR) • Condenser tube leak (BWR) • Startup of an idle recirculation pump in a cold loop (BWR) • Reactor overpressure with delayed scram The individual event sections of the SRP address specific AOOs and their appropriate variations (e.g., design-specific variations). Anticipated transients without scram (ATWSs) are AOOs in which a reactor scram is demanded but fails to occur because of a common-mode failure in the reactor scram system. ATWS events, therefore, are AOOs that postulate complete failure of the required (single-failure proof) protection system. As such, they are beyond the design basis, and consequently, ATWS events are addressed separately (see SRP Section 15.8). Postulated accidents are unanticipated occurrences (i.e., they are postulated but not expected to occur during the life of the nuclear power plant). Postulated accidents are also known as Condition IV events in the unofficial ANS standards. 15.0-4 Revision 3 - March 2007 The following are some examples of postulated accidents in PWRs and BWRs of current designs: • Major rupture of a pipe containing reactor coolant up to and including double-ended rupture of the largest pipe in the reactor coolant pressure boundary (PWR and BWR) • Ejection of a control