Document: NUREG-0800
Document ID: 2349ea77-1f6e-45e4-a2df-f56249a774f1
Document Type: srp
Title: CONTROL ROD DRIVE SYSTEMS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070364.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.4
CFR Part: 
CFR Title: 

Content:
requirements. Technical Rationale:47 The technical rationale for application of the above acceptance criteria to the CRDS is discussed in the following paragraphs: 1. GDC 1 and 10 CFR 50.55a establish requirements regarding the quality standards to be applied to the CRDS. Specifically, 10 CFR 50.55a identifies the ASME Code requirements, Code editions, and addenda which must be applied to pressure-retaining portions of the CRDS that are of the highest importance to safety and Regulatory Guide 1.26 identifies acceptable standards to be applied for pressure-retaining portions of the CRDS that are less important to safety but which may contain radioactive material. The CRDS is an independent reactivity control system designed to ensure the capability to control reactivity changes in the reactor under both normal operating and accident conditions. The fuel cladding and reactor coolant pressure boundary (RCPB) are protected by CRDS safety functions which include insertion of adequate negative reactivity to preserve these fission product barriers under specified conditions. In addition, the CRDS comprises a portion of the RCPB thus providing a barrier to the release of fission products. The application of GDC 1 and 10 CFR 50.55a requirements to the design, fabrication, erection and testing ensures the CRDS meets quality standards that are adequate to provide assurance that these safety functions will be performed. 2. GDC 2 establishes requirements regarding the ability of the CRDS to withstand the effects of an earthquake. The CRDS must satisfy seismic Category I requirements and be capable of controlling reactivity when subject to a seismic disturbance thereby ensuring that the fission process can be rapidly terminated under the same conditions. Consequently, plant protection and safety is augmented by the capability of the CRDS to perform its safety function under earthquake conditions. 3. GDC 14 establishes requirements regarding the RCPB portion of the CRDS. The CRDM