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.