Situation awareness in outage work – A study of events occurring in U.S. nuclear power plants between 2016 and 2020

Abstract

In this study, we sought to identify if human errors responsible for incidents occurring during scheduled outage periods in nuclear power plants correspond to situation awareness errors in perception, comprehension, or projection. We also sought to identify factors contributing to situation awareness errors at all levels. To do this, we analysed 58 events occurring during planned nuclear power plant outages between 2016 and 2020, as documented in U.S. Licensee Event Reports (LERs). Of the human errors analysed in these events, 14 were classified as situation awareness errors related to perception (Level 1 errors), 30 were classified as situation awareness errors related to comprehension (Level 2 errors), and an additional 14 were classified as situation awareness errors related to projection (Level 3 errors). Furthermore, we found that insufficient procedure use was identified in the LERs as a factor contributing to most errors occurring at Level 1, whereas insufficient procedures was identified to contribute to most errors occurring at Level 2 and 3.