Document: NUREG-0800
Document ID: 67e3fd64-e6a4-4522-b90f-4184c2f5b357
Document Type: srp
Title: FUNCTIONAL DESIGN OF CONTROL ROD DRIVE SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070540139.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.6
CFR Part: 
CFR Title: 

Content:
tional occurrences. Preventing excessive cladding damage in the event of anticipated transients ensures maintenance of the integrity of the cladding as a fission product barrier. 8. 10 CFR 50.62(c)(3) requires that each BWR have an alternate rod injection system that is diverse (from the reactor trip system) from sensor output to the final actuation device. In addition, the alternate rod injection system must have redundant scram air header exhaust valves. There is a potential within all reactor trip system designs for common cause failures of identical or similar components to result in a failure to trip the CRDS. The anticipated transient without scram (ATWS) requirements address this potential and reduce the susceptibility to common mode failures in the scram systems. For BWRs, one method of providing diversity in the alternate rod injection system is the use of an “energize to trip” circuit versus a “de-energize to trip” circuit in the output devices of the scram system and the provision for redundant scram air header exhaust valves. Implementing the requirements of 10 CFR 50.62(c)(3) enhances plant safety by reducing the risk resulting from an ATWS event at BWR plants and by providing mitigation capability to permit a safe shutdown of the plant should an ATWS event occur. 9. 10 CFR 52.47(b)(1) and 10 CFR 52.80(a) require that ITAAC be identified for DCs and COLs. Because the DC or license approval is being granted before facility construction, there is a potential that the as-built configuration of a facility may not meet the requirements of the DC or COL as granted. The purpose of the ITAAC is to ensure that the as-built facility meets the requirements set forth in the DC or COL. III. REVIEW PROCEDURES The reviewer will select material from the procedures described below, as may be appropriate for a particular case. These review procedures are based on the identified SRP acceptance criteria. For deviations from these acceptance criteria, the staff