A context-specific approach toward human reliability assessment

摘要

As individual pieces of equipment become more and more reliable and as maintenance improvements extend their life,the human contribution to the risk of system operation which has always been significant is becoming evermore important.Approaches which address the assessment of human reliability have been around since the late sixties~[1],and they have made significant and useful contributions to the identification of the significance of human errors in the risk of operation of nuclear facilities in particular.However there have been significant problems in using these approaches to determine where and to what degree changes in human impacting elements would be cost effective.The reason for this problem is that,just as in the case of early equipment failure assessments,conventional Human Reliability Analysis (HRA) approaches are,to a great degree,context indepeneent.That is the evaluations serve,much as equipment generic data did,to indicate the general magnitude of the risk contributioon,but did not attempt to highlight the specific areas and specific values of potential imporvements.For this reason plant managers were forced to rely ocmpletely on the expert judgment of the HRA analysis in the determination of which changes would be effective.Further,even with this judgment,it was often difficult to justify the risk reduction credit that should be given for changes made to reduce the human error contribution.