An Integrated Risk Assessment Process of Safety-Related Digital I&C Systems in Nuclear Power Plants

Journal Article · Mon Jul 11 00:00:00 EDT 2022 · Nuclear Technology

DOI:https://doi.org/10.1080/00295450.2022.2076486· OSTI ID:1974871

Zhang, Hongbin ^[1]; Bao, Han ^[1]; Shorthill, Tate ^[2]; Quinn, Edward ^[3]

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1. Idaho National Laboratory (INL), Idaho Falls, ID (United States)
2. University of Pittsburgh, PA (United States)
3. Technology Resources, Dana Point, CA (United States)

Upgrading the existing analog instrumentation and control (I&C) systems to state-of-the-art digital I&C (DI&C) systems will greatly benefit existing light water reactors. However, the issue of software common cause failure (CCF) remains an obstacle in terms of qualification for digital technologies. Existing analyses of CCFs in I&C systems mainly focus on hardware failures. With the application and upgrading of new DI&C systems, design flaws could cause software CCFs to become a potential threat to plant safety, considering that most redundancy designs use similar digital platforms or software in their operating and application systems. With complex multilayer redundancy designs to meet the single failure criterion, these I&C safety systems are of particular concern in U.S. Nuclear Regulatory Commission licensing procedures. In Fiscal Year 2019, the Risk-Informed Systems Analysis (RISA) Pathway of the U.S. Department of Energy’s Light Water Reactor Sustainability Program initiated a project to develop a risk assessment strategy for delivering a strong technical basis to support effective, licensable, and secure DI&C technologies for digital upgrades and designs. An integrated risk assessment for the DI&C process was proposed for this strategy to identify potential key digital-induced failures, implement reliability analyses of related digital safety I&C systems, and evaluate the unanalyzed sequences introduced by these failures (particularly software CCFs) at the plant level. Here this paper summarizes these RISA efforts in the risk analysis of safety-related DI&C systems at Idaho National Laboratory.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: AC07-05ID14517
• OSTI ID: 1974871
• Report Number(s): INL/JOU-21-65396-Revision-0
• Journal Information: Nuclear Technology, Journal Name: Nuclear Technology Journal Issue: 3 Vol. 209; ISSN 0029-5450
• Publisher: Taylor & Francis
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
DI&C
common cause failure
consequence analysis
hazard analysis
reliability analysis
risk assessment