LESSONS LEARNED CASE STUDIES BASED ON US DIGITAL OPERATING EXPERIENCE

摘要

In late 2007 and early 2008, EPRI, working with a principal investigator and a team of industry experts, performed a review of over 300 US operating experience reports spanning 20 years. The primary objective of the research was to extract insights that can be applied to improve Diversity & Defense in Depth (D3) methods for protecting plants against I&C related Common Cause Failures, which is published in [EPRI TR 1016731].The basic research developed for [TR 1016731] also provided a wealth of lessons learned from digital system events that can be used by utility engineers to improve their knowledge, experience and techniques so they can reduce the likelihood of similar problems in the future. To that end, EPRI commissioned a blue chip project to extract the common themes in various categories of digital events and develop a series of case studies based on typical causes and associated lessons learned.EPRI, working with a principal investigator and a utility working group made up of highly experienced digital system professionals, selected five digital events with wide ranging lessons learned for further development into case studies. The working group required that the case studies be delivered in the form of multimedia, interactive modules that can be easily deployed via their corporate intranets for direct access by utility engineers without leaving their work locations.The lessons learned from the five different case study events cover various technical topics, including requirements analysis, failure modes and effects analysis, testing coverage, equipment qualification (e.g., EMI), human performance, procedure validation, material workmanship (e.g., wire termination quality), software verification and validation, and defensive measures against common cause failure mechanisms.The multimedia aspect of this project enables the case studies to be viewed using any standard web browser with a flash add-in. The result is that each case study is highly interactive and intuitive, about 20 minutes in length, with a common theme of a fictionalized plant, circumstances before, during and after the event, the resulting impact on plant operations, the results of the root cause analysis, lost opportunities for identifying latent defects during the modernization project, and key lessons learned.This paper is about the preparation of these 5 case studies, their event causes, and their lessons learned.