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:
proposed DI&C system or component modification.  RG 1.152, “Criteria for Programmable Digital Devices in Safety-Related Systems of Nuclear Power Plants,” provides guidance on measures to ensure communication independence and control of access. For an application that describes cybersecurity design features intended to address cybersecurity vulnerabilities, the NRC staff’s review of these features is limited to ensuring that they do not adversely affect or degrade the safety-related system’s reliability or its capability to perform its safety functions. If licensees or applicants consider cybersecurity design features, they should include measures to ensure that safety-related I&C systems do not present an electronic path that could enable unauthorized access to the plant’s safety-related systems. (For BTP 7-19-7 Revision 9 — May 2024  example, the use of a hardware-based unidirectional device is one approach the NRC staff would consider acceptable for implementing such measures.)  RG 1.174, “An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis,” describes an approach that is acceptable to the NRC staff for developing risk-informed applications for licensing-basis changes that consider engineering issues and apply risk insights.  RG 1.200, “Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities,” describes one approach acceptable to the NRC staff for determining whether a base probabilistic risk assessment (PRA), in total or in the portions that are used to support an application, is sufficient to provide confidence in the results, such that the PRA can be used in regulatory decision-making for light-water reactors.  NUREG/CR-6303, “Method for Performing Diversity and Defense-in-Depth Analyses of Reactor Protection Systems,” issued December 1994, summarizes several D3 analyses performed after 1990. It presents a method for