Licensing process for upgrading I&C systems at nonpower production or utilization facilities (NPUFs)

For digital I&C changes being reviewed by the NRC or performed under 10 CFR 50.59, reasonable assurance of low likelihood of failure is derived from assessment of factors involving system design features, the quality of the design processes employed, and the operating history of the software and hardware used (i.e., product maturity and in-service experience). The assessment must result in a determination that there is reasonable assurance that the digital I&C modification will exhibit a low likelihood of failure by considering the aggregate of these factors. Additionally, the analysis must contain sufficient detail either by reference or by direct statements, such that an independent third party can verify the conclusions. If the licensee determines that the proposed modification cannot be performed under 10 CFR 50.59, the licensee can redesign the proposed modification so that it can be implemented without requiring a license amendment. In lieu of 10 CFR 50.59, a licensee can still pursue performing proposed modifications as a license amendment under 10 CFR 50.90. Significant changes are pending for the 10 CFR 50.59 guidance for digital I&C, and licensees should stay current with these changes. Guidance is provided in the ISG for Chapter 7 for NUREG-1537 for LARs and new facilities.