Analysis of an Operators´ Performance Time and Its Application to a Human Reliability Analysis in Nuclear Power Plants

With a scarcity of empirical data, much of the input regarding a human reliability analysis (HRA) is dependent on an analysts´ subjective judgment, which is one of the major causes of a high uncertainty in the results of an HRA. When considering that risk-informed activities require the probabilistic safety assessment (PSA) quality to be as high as possible, an HRA should be performed by using a systematic method with realistic plant specific data to meet the established requirements for risk-informed applications. In order to obtain more objective HRA results, data extracted from real experiences or simulators is essential. This paper presents a human performance analysis of the emergency tasks for nuclear power plants (NPPs) to support an HRA. Using the full-scope simulator of a reference plant, more than 110 simulator records with six emergency scenarios were gathered and analyzed to generate an operators´ performance time such as the time taken to diagnose what event has occurred, and the time to execute a procedural step or a task. A sensitivity analysis for an HRA has also been performed by using an operators´ performance time.