A probabilistic method for analyzing the reliability effect of time and organizational factors

Two essential factors – with a great margin for improvements – determine the reliability of a human performance procedure under emergency conditions: time and organization. Intelligent use of error tolerating design will result in a large time window available to emergency response. A good organization will reduce the time required for emergency response. Here, a new probabilistic method for analyzing human reliability under emergency conditions is presented. It uses time window and organization input data. The method enables a quantitative comparison between several organization alternatives for an emergency response. In this method, the whole emergency procedure is subdivided into single steps. For these the performance time distribution can be assessed with relatively high accuracy. Several computer codes are presented which are able to calculate the overall performance time distribution for almost every given procedure structure determined by technical and organizational factors. One example concerning nuclear power plant emergency response is given to demonstrate the practicability of this approach.