Document: NUREG-0800
Document ID: 042bc5c0-5de0-44b4-9599-6c131e20eb7a
Document Type: srp
Title: FUNCTIONAL DESIGN OF CONTROL ROD DRIVE SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070413.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.6
CFR Part: 
CFR Title: 

Content:
r mitigates the consequences associated with postulated accident scenarios. The CRDS needs to be designed such that the ability to perform these safety-related functions are not compromised by adverse environmental conditions. Compliance with GDC 4 assures that the CRDS will remain functional under adverse postulated environmental conditions and provide essential reactor shutdown capabilities. 2. General Design Criterion 23 requires that the protection system be designed to fail into a safe state if adverse conditions or environments are experienced. The control rod drive system provides positive core reactivity control through the use of movable control rods. The movable control rods provide reactivity control for all modes of operation inclusive of all plant conditions from the cold shutdown condition to the full load condition. The control rod drive system, 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 General Design Criteria 23 provides assurance that the protection system in conjunction with the control rod drive system will fail in a manner that prevents damage to the fuel cladding by providing positive control and prevention of excessive reactivity changes during a failure. 3. General Design Criterion 25 requires that the protection system be designed to assure that specified acceptable fuel design limits are not exceeded for any single malfunction of the reactivity control systems. The control rod drive system provides the motive force for the moveable control rods providing one functional method for reactivity control. Meeting the requirements of General Design Criteria 25 by designing these systems to withstand single failures, ensures that a single malfunction of the rod control drive system, such as accidental withdrawal, will not prevent proper