Document: NUREG-0800
Document ID: fe8ec6c2-e960-404c-854f-55c77bde1672
Document Type: srp
Title: NUREG-0800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML2400/ML24005A077.pdf
Revision Date: 2024-05
Chapter: 7
Section ID: 7
CFR Part: 
CFR Title: 

Content:
cceptable fuel design limits are not exceeded. The second reactivity control system shall be capable of reliably controlling the rate of reactivity changes resulting from planned, normal power changes (including xenon burnout) to assure acceptable fuel design limits are not exceeded. One of the systems shall be capable of holding the reactor core subcritical under cold conditions. 2. Relevant Guidance The following documents provide useful guidance in the evaluation of possible CCFs affecting DI&C systems:  SECY-93-087, item II.Q, as clarified by SRM-SECY-93-087, item 18, describes the NRC position on defense against potential common-mode failures in DI&C systems.  SECY-18-0090, “Plan for Addressing Potential Common Cause Failure in Digital Instrumentation and Controls,” dated September 12, 2018, describes the NRC staff’s plan to clarify the guidance for evaluating and addressing potential CCFs of DI&C systems. BTP 7-19-6 Revision 9 — May 2024  SECY-22-0076, “Expansion of Current Policy on Potential Common-Cause Failures in Digital Instrumentation and Control Systems,” dated August 10, 2022, describes the NRC staff’s proposal to clarify, further risk-inform, and expand the NRC’s policy for evaluating and addressing potential CCFs of DI&C systems. Specifically, the staff requested that the Commission expand the current policy to allow the use of risk-informed approaches to demonstrate the appropriate level of defense in depth, including the option of not providing diverse automatic actuation of safety functions. The staff also requested that this expanded policy apply to all types of nuclear power plants.  The supplement to SECY-22-0076, dated January 23, 2023, clarifies the NRC staff’s proposal in SECY-22-0076.  In SRM-SECY-22-0076, dated May 25, 2023, the Commission approved the staff’s recommendation in SECY-22-0076, with edits, and provided directions to the staff. Specifically, the Commission directed that the proposed revision