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:
om equipment failures and from external events. The CRDS provides the capability to safely shut down the reactor during normal operations and anticipated operational occurrences and either prevents or mitigates the consequences associated with postulated accident scenarios. The design of the CRDS must ensure that the ability to perform these safety-related functions is not compromised by adverse environmental conditions. Compliance with GDC 4 ensures that the CRDS will remain functional under adverse postulated environmental conditions and provide essential reactor shutdown capabilities. 2. GDC 23 requires that the protection system be designed to fail into a safe state in the event of adverse conditions or environments. The CRDS provides positive core reactivity control through the use of movable control rods. The movable control rods provide reactivity control for all modes of operation, including all plant conditions from the cold shutdown condition to the full-load condition. The CRDS, in conjunction with the protection system, must actuate the control rods to effect safety-related functions when necessary to provide core protection during normal operation, anticipated operational occurrences, and accidents. Meeting the requirements of GDC 23 provides assurance that the protection system in conjunction with the CRDS will fail in a manner that prevents damage to the fuel cladding by providing positive control and preventing excessive reactivity changes during a failure. 3. GDC 25 requires that the protection system be designed to ensure that specified acceptable fuel design limits are not exceeded for any single malfunction of the reactivity control systems. The CRDS provides the motive force for the moveable control rods providing one functional method for reactivity control. Meeting the 4.6-7 Revision 2 - March 2007 requirements of GDC 25 by designing these systems to withstand single failures ensures that a single malfunction of the rod control drive system,