Analysis of human performance problems at the Swedish nuclear power plants

The operation of all Swedish nuclear power plants during the last five years was studied with respect to human performance problems by analyzing all scrams and licensee event reports (LERs). The study covers 165 scrams and 1318 LERs. 39% of the scrams and 27% of the LERs on average for the years 1983-7 were found to be caused by human performance problems. Among the items studied, emphasis was placed on the analysis of the causal categories involved in human performance problems resulting in plant events. The most significant causal categories appear to be work organization, procedures not followed, workplace ergonomics, and human variability. The statistical variation, in time, of the analyzed categories does not allow the identification of any robust trend. It is concluded that so far there is no reason for alarm as far as the frequency and consequences of human performance problems are concerned.<>