EPRI human reliability analysis calculator

Human reliability analysis (HRA) remains an area that contributes significantly to differences in assessments of risk for similar plants and, in some cases, by different analysts for the same plant. A variety of HRA methods currently exist that can yield dramatically different results. These inconsistencies can affect the ability to draw clear insights from probabilistic risk/safety assessment (PRA/PSA) applications. The differences in HRA results are also becoming increasingly significant as the use of quantitative risk results grows as part of the move toward risk-informed regulation. Further, the use of PRA's to support daily operations has produced an increasing need to be able to update/calculate human error probabilities quickly and consistently. There is, therefore, a clear need to develop a tool using a standardized method to aid PSA analysts in assessing human reliability in a consistent and defendable manner. To address these needs, EPRI founded the EPRI / PRA Tools Users Group to develop an HRA tool to interface with EPRI Risk & Reliability Workstation products NUPRA, CAFTA, and RISK SPECTRUM. The primary objective of the EPRI / PRA Tools Users Group is to standardize HRA methods in order to obtain comparable results when considering plants that are similar with respect to design, procedures, training, and man-machine interface. The key, long-term goal for the group is to enable the industry to converge to on a set of common methods. In 2001, the EPRI / PRA Tools Users Group developed the first version of a tool called the EPRI HRA Calculator which embodies a set of HRA guidelines and meets the objectives defined above. This paper summarizes the features and functions of the new EPRI Human Reliability Analysis Calculator.