This NUREG-0471[1] item was an ACRS generic concern that initially addressed the common mode failure of identical components exposed to identical or nearly-identical conditions or environments. This concern was later expanded to include other types of multiple failures for which the consequences and probabilities cannot be predicted by application of the single failure criterion, such as use of the same sensors or components for both control and protection systems, sequential multiple failures due to a domino effect, or simultaneous multiple failures due to a single fault.
The safety concern of this issue was addressed in Issues A-9, A-17, A-30, A-35, B-56, and B-57.
[1] NUREG-0471, "Generic Task Problem Descriptions (Categories B, C, and D)," U.S. Nuclear Regulatory Commission, June 1978.
Page Last Reviewed/Updated 06/24/2025