Document: NUREG-0800
Document ID: 97b8d603-4b3f-40a3-9dbb-e89b68e654c6
Document Type: srp
Title: ANTICIPATED TRANSIENTS WITHOUT SCRAM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350327.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.8
CFR Part: 
CFR Title: 

Content:
REVIEW RESPONSIBILITIES Primary - Reactor Systems Branch .(RSB) Secondary - None I. AREAS OF REVIEW Ant.icipated transients are transients expected to occur during the life of the plant. Anticipated transients without scram (ATWS) are those low probability events in which an anticipated transient occurs and is not followed by an auto- matic reactor shutdown (scram) when required. The failure of the reactor to shut down quickly during these transients can lead to unacceptable reactor coolant system pressures and to fuel damage. Typical transients that may have unaccept- able consequences in a PWR if there is a scram failure are: loss of feedwater, loss of load, turbine trip, inadvertent control rod withdrawal, loss of ac power, loss of condenser vacuum. For a boiling water reactor (BWR), unacceptable consequences may occur for a closure of main steamline isolation valves with failure to scram. The NRC.staff's studies and findings regarding ATWS are presented in References 1 and 2. The Commission is presently considering rulemaking on the ATWS issue, which would determine what plant modifications are required to mitigate ATWS consequences to acceptable levels. Prior to completion of Commission rulemaking, the following interim requirements are in effect. The RSB will coordinate the other branch reviews that interface with the overall review. The ICSB reviews the adequacy of the design of the BWR recirculation pump trip as part of its primary review responsibility of SRP Section 7.2. The PTRB reviews the emergency procedures for ATWS as part of its primary responsibility of SRP Section 13.5. The OLB reviews the operator training program for ATWS events. as part of its primary review responsibility of SRP Section 13.2. II. ACCEPTANCE CRITERIA .The following design criteria apply: Rev. 1 - July 1981 USNRC STANDARD REVIEW PLAN Standard review plans are prepared for the guidance of the Office of Nuclear Reactor Regulation staff responsible for the review of applications to