Human error probabilities from operational experience of German nuclear power plants, Part II

This paper is a continuation of an earlier publication (Preischl et al., Reliab Eng Syst Saf 2013;109:150–9) and presents the second part of a project aimed to collect human reliability data from the operational experience of German nuclear power plants. We employ a method which utilizes the German licensee event reporting system to gather the data. In this way, in addition to the data already presented in the previous paper, another 30 estimates for human error probabilities (HEP) are obtained. Moreover, a new method to access parts of the operational experience below the notification threshold of the German event reporting system is described. This method is demonstrated in cooperation with a reference nuclear power plant, resulting in 18 additional HEP estimates. As a result of both projects altogether 74 usable HEP estimates for a wide variety of tasks were derived. Notably, a number of them concern memory related or cognitive errors. A comparison with the THERP database shows that for 48 of these HEP estimates THERP provides no data, whereas in the 26 cases where THERP proposes a HEP it agrees with our data in all but eight cases.