Peer Review of the Stability Analysis of Dike C at the Kingston Fossil Plant

TVA Office of the Inspector General retained Marshall Miller & Associates, Inc. (Marshall Miller) to conduct a peer review of the report entitled "Report of Geotechnical Exploration and Slope Stability for Dike C," prepared by Stantec Consulting Services, Inc. (Stantec) of Lexington, Kentucky. In summary, it is Marshall Miller's opinion that Stantec generally performed a reasonable scope of investigation for the portion of Dike C covered in its report and applied appropriate investigative methods and evaluation techniques. However, according to Marshall Miller, Stantec applied site-wide characterization and application of shear strength parameters even though areas of significantly weaker material were identified. In addition, there was a lack of information on seepage and material conditions nearer the downstream toe of Dike C, which caused additional uncertainty about the Stantec study and its associated conclusions and opinions about the Dike C conditions. To address Marshall Miller's report, TVA management had Stantec and AECOM review and respond to the findings in this report. TVA management and its contractors disagreed with many of the findings and recommendations. Marshall Miller provided additional comments in response to AECOM and Stantec responses. In summary, Marshall Miller stands by the findings in the report and disagrees with some of the methodologies used by Stantec to evaluate Dike C. However, Marshall Miller feels that the Dike C improvement planned actions, referenced in the Stantec and AECOM responses, address or will address most of its findings and recommendations. The remaining findings and recommendations not fully addressed were not considered substantial.