Improving the Value of Excavations Through Indirect Inspection and Engineering Assessments

U.S. nuclear power plants are implementing a life cycle management approach to underground and buried pipe integrity management. The last few years have been spent gathering information about these systems and performing relative risk ranking analyses. The next stage of this process was to further refine the risk prioritization by gathering additional indirect performance information to qualitatively characterize the effectiveness of existing corrosion control measures, thereby refining the prioritization of locations with highest potential for corrosion activity. Once these locations are better understood, strategic quantitative Direct Examination techniques (i.e., NDE) can be used to inspect and then evaluate the fitness for service and remaining life. This paper provides a brief review of the increased interest in performing excavations at nuclear sites and will present corrosion engineering techniques that uniquely evaluate both the internal and external corrosion threats using ACCORDION© and APEC©, as well as an overall strategy designed to help maximize the value of each excavation. Application of the systematic methodology presented as part of a NEI 09-14 Reasonable Assurance process [Ref 1] can increase a site’s likelihood for the proactive detection of corrosion degradation — which is a key objective for the assurance of structural and/or leakage integrity of buried piping.Copyright © 2012 by ASME