Proposed Approach for Reviewing Changes to Risk-Important Human Actions (NUREG/CR-6689)

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Publication Information

Manuscript Completed: September 2000
Date Published: October 2000

Prepared by:
J.C. Higgins, J.M. O'Hara

Brookhaven National Laboratory
Upton, NY 11973-5000

P. Lewis, NRC Project Manager

Prepared for:
Division of Systems Analysis and Regulatory Effectiveness
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

NRC Job Code Y6022

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The U.S. Nuclear Regulatory Commission (NRC) is addressing the human performance aspects of changes to operator actions that are credited for safety, especially those involving changes in the licensing basis of the plant; e.g., use of manual action in place of an automatic action for safety system operations. This report proposes risk-informed guidance and acceptance criteria for the review of licensee proposals addressing such modifications. The review method uses a graded, risk-informed approach and provides guidance for reviewing the human performance aspects of changes to plant systems and operations. The evaluation method uses a two-phase approach. The first phase is a screening analysis of the plant modification and the affected human actions (HAs) to determine their risk importance. Three risk regions are defined: high, medium, and lower risk regions. In the second phase, HAs are reviewed using human factors engineering criteria to ensure the proposed HA can be reliably performed when called upon in the plant. HAs in the high-risk region receive a detailed review and those in the medium-risk region receive a less detailed review that is commensurate with their risk. For HAs falling into the lower-risk region, no human factors review is performed.

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