The results of a study that was jointly sponsored by the U.S. Department of Energy and the Electric Power Research Institute are described in this report. The purpose of the study was to 1) estimate the number of failed fuel assemblies and damaged fuel assemblies (i.e., ones that have sustained mechanical or chemical damage but with fuel rod cladding that is not breached) in storage, 2) categorize those fuel assemblies, and 3) prepare this report as an authoritative, illustrated source of information on such fuel. Among the more than 45,975 spent light-water reactor fuel assemblies currently in storage in the United States, it appears that there are nearly 5000 failed or damaged fuel assemblies • i i i ACKNOWLEDGMENTS This report summarizes a jointly sponsored study conducted by Pacific Northwest Laboratory (PNL) for the Commercial Spent Fuel Management Program, which is sponsored by the U.S. Department of Energy (DOE) under Contract DE-AC06-76RLO 1830, and for the Electric Power Research Institute (EPRI) under Agreement RP 2062-11. The principal investigator was W. J. Bailey of the Reactor Systems, Fuels, and Materials Department. The author acknowledges the contributions of R. C. Walling (Waste Systems Department) on input for Section 3.5 and Appendix A, D. E. Blahnik (Reactor Systems, Fuels, and Materials Department) on Appendix A, and C. E. Beyer (Reactor Systems, Fuels, and Materials Department) as a peer reviewer. Grateful appreciation is expressed to DOE for guidance and support on the project and to R. W. Lambert of EPRI for continuing guidance on the study and for supporting the wet storage technology program • xi