Human error in events involving wrong unit or wrong train

The Office for Analysis and Evaluation of Operational Data (AEOD) of the Nuclear Regulatory Commission (NRC) undertook a special study of recent events that were similar to one discovered on April 19, 1983, at Turkey Point Plant Unit 3. The AEOD identified 26 additional events during the period from January 1981 to approximately August 1983 which had characteristics similar to the Turkey Point 3 event, i.e., losses of safety system function that resulted because of human errors involving operations on an incorrect train or unit. Of the 27 total reported events, 19 resulted from human error during maintenance and surveillance testing, 16 of which occurred near full power. The corrective actions taken in most of the events were improvements in procedures and/or improvements in identification by color coding and increasing the size and prominence of labeling. In a number of events reviewed in this study, verification of correct performance was either not performed or was performed inadequately. Poor and incomplete licensee verification procedures, a weak licensee management commitment to independent verification, and imprecision in NRC requirements in terms of scope of requirements and definition of terms were found to contribute to lessening the effectiveness of independent verification activities