Human/system reliability in a changing environment

Changes in the power plant field are to try to reduce costs, while increasing both safety and availability. This leads to an examination of both HRA models and their use. One such use is to examine the effectiveness of HSI. The paper discusses the details of a HRA model and its use to help evaluation of HSI. The model was used in the study of International Space Station safety and variations in HSI effectiveness. Here the techniques were used to evaluate the effectiveness of procedure support systems and their potential advantages over human factors modification of displays and indicators.