Document: NUREG-0800
Document ID: 846ded8e-04ea-4031-8f64-62690ca967b6
Document Type: srp
Title: ANTICIPATED TRANSIENTS WITHOUT SCRAM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070570008.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.8
CFR Part: 
CFR Title: 

Content:
l water level must be lowered to a level below the feedwater spargers that will allow vessel steam to preheat the cold feedwater. ii. if unstable power oscillations are detected following a failure to scram, boron injection through the SLCS must be initiated manually. 2. For Pressurized Water Reactors (PWRs): A. Provide measures to automatically initiate the auxiliary (or emergency) feedwater system and a turbine trip under conditions indicative of an ATWS. This equipment shall be independent and diverse from the reactor trip system from sensor output to the final actuation device. 15.8-5 Revision 2 - March 2007 B. Combustion Engineering or Babcock and Wilcox reactors applicants shall have provision for a scram system that is independent and diverse from the reactor trip system, from sensor output to the points of interruption of power to the control rods. C. These system and equipment shall be demonstrated to provide reasonable assurance that unacceptable plant conditions do not occur in the event of an anticipated transients D. The reactor coolant system (RCS) pressure shall not exceed ASME Service Level C limits (approximately 22 MPa or 3200 psig) containment safety parameters (e.g., temperature or pressure) should not exceed design limits 3. For Evolutionary Plants A. For evolutionary plants where the ATWS rule does not explicitly require a diverse scram system, the applicant may provide either of the following: i. A diverse scram system satisfying the design and quality assurance criteria specified in SRP Section 7.2 ii. Demonstrate that the consequences of an ATWS event are within acceptable values. B. For evolutionary plants, some of the equipment required to satisfy the rule may not be apply. For example, passive BWRs do not have recirculation pumps; therefore, these designs cannot provide equipment to trip them as required by the rule. For these designs provision of an equivalent action such as reducing the vessel water level may be acceptable. C.