Document: NRC Regulatory Guide
Document ID: 26c3e31f-c018-4aee-b926-6db849b72a5a
Document Type: regulatory_guide
Title: Guidelines for Environmental Qualification of Safety-Related Computer-Based Instrumentation and Control Systems in Nuclear Power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0630/ML063040591.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.209
CFR Part: 
CFR Title: 

Content:
nor is the probability of achieving the overall safety goals. However, on the basis of a qualitative assessment of existing literature, experience with military applications of digital I&C, commercial industry experience, and experience in the nuclear industry, computer-based I&C systems have the potential to induce an undesirable safety consequence less predictably than similar analog systems. Therefore, the staff infers a positive correlation between addressing qualification of computer- based I&C systems for nuclear power plant environments and achieving safety goals, based on the negative effects of the alternate choice. In the following summary, an impact is a cost in schedule, budget, or staffing or an undesired property or attribute that would accrue from taking the proposed approach. Both values and impacts may be functions of time. 3.1 Alternative 1: Take No Action This alternative has a perceived cost-benefit advantage because it includes no startup activities. It also provides flexibility because each applicant or licensee would develop its own technical basis to demonstrate that its new or modified I&C system complies with NRC regulations. However, in the absence of explicit, definitive guidance on acceptable practices for qualification of all safety-related computer-based I&C systems, the NRC staff may receive applications or requests to review safety questions without adequate supporting evidence such as certificates of conformance and design specifications. As a result, the NRC may have to make time-consuming and costly requests for additional information. In addition, no established basis for endorsing the current national consensus standard for digital I&C qualification would be available. The absence of an identified set of guidelines could have adverse effects on the level of staff effort required to conduct reviews and to ensure consistency among reviewers for each I&C system modification. Thus, NRC staff reviews would take longer and require