Document: NUREG-0800
Document ID: 825fe003-d78e-433f-8e46-8e2cb989ac88
Document Type: srp
Title: FUNCTIONAL DESIGN OF CONTROL ROD DRIVE SYSTEM
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340589.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.6
CFR Part: 
CFR Title: 

Content:
The CRDS, P&IDs, layout drawings, and component description and character- istics are reviewed by the ASB to verify that essential portions of the system are correctly identified and are isolable from non-essential portions. The essential portions should be protected from the effects of high or moderate energy line breaks. Layout drawings of the system are reviewed to assure that no high or moderate energy piping systems are close to the 4.6-3 Rev 1 - July 1981 CRDS, or that protection is provided from the effects of high or moderate energy pipe breaks. 3. For plants containing control rod drive cooling systems (e.g., using air or water as coolant), the description and drawings are reviewed to determine that the systems meet the design requirements. Essential equipment should be delineated in the SAR. The major function of the cooling system in PWRs is to cool the drive mechanism and remove heat from the CRDS motors to preclude motor burnout or damage. Failure of a CRDS motor could result in a rod drop. In BWRs, the major function of the cooling water is to cool the drive mechanism and its seals to preclude damage resulting from long-term exposure to reactor temperatures. The control rod drive hydraulic system includes the cooling function as part of its design. The ASB reviewer confirms by failure modes and effects analysis that the cooling system is capable of maintaining the CRDS temperature below the applicant's maximum temperature criterion. The ICSB reviewer in SRP Section 7.2 confirms that there are sufficient instrumentation and controls available to the reactor operator to provide information in the control room to monitor the CRDS conditions, including the more significant parameters such as coolant flow, temperature, and pressure and stator temperature. 4. In coordination with the MEB, the ASB reviews the functional tests of the CRDS as related to rod insertion and withdrawal and scram operation and time. The reviewers check the elements of the test