Document: NRC Regulatory Guide
Document ID: 65325e1a-3033-4f91-a5fa-fcd1286b72ec
Document Type: regulatory_guide
Title: Dedication of Commercial-Grade Digital I&C Items for Use in Nuclear power Plants
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2200/ML22003A180.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.250
CFR Part: 
CFR Title: 

Content:
s a combination of methods, including Methods 2 and 4, for digital I&C items. As documented in the NRC staff safety evaluation report for TR-106439, the NRC staff determined that TR-106439 contains an acceptable method for dedicating commercial-grade digital equipment for use in nuclear power plant safety applications and meets the requirements of 10 CFR Part 21. The NRC staff further concluded that when digital equipment is dedicated using the methods described in TR-106439, it may be considered equivalent to digital equipment designed and manufactured under a 10 CFR Part 50, Appendix B, QA program. The NRC staff noted that licensees referencing TR-106439 would need to document application-specific details about the dedication process and specific critical characteristics. Section 4.2 of TR-106439 provides guidance for defining and verifying critical characteristics that will provide reasonable assurance that the item will perform its intended safety function. This DG-1402, Page 5 guidance states that “a complete definition of requirements, including hardware, software, human-machine interface, quality, and reliability requirements, is an important prerequisite for dedication of a commercial-grade item. It is especially important for digital equipment, where experience has shown that many of the problems that occur are due to inadequate definition of requirements. For software-based equipment, in addition to design requirements for the intended functions and anticipated failure modes, it is particularly important to identify requirements related to unused, and unintended or prohibited functions.” The types of critical characteristics considered within TR-106439 for many types of devices include physical or performance characteristics. For digital equipment, however, a third type of characteristic, referred to as “dependability,” is identified as being important when dedicating digital equipment that includes software. Dependability characteristics address