The　root　cause　of　the　failure　of　a　cracked　blade　in　the　low　pressure　turbine　of　a　nuclear　power　plant　was　investigated.　The　low　clearance　between　the　blade　and　the　disk　caused　a　sliding　motion,　which　led　to　fretting　wear　during　in-service　operations.　The　crack　in　the　blade　was　determined　to　have　initiated　under　fretting　wear　and　propagated　with　high　cycle　fatigue　by　means　of　analyzing　the　fracture　surface　of　the　failed　blade.　Micro　oxide　particles　were　detected　from　the　Electron　Dispersive　Spectroscopy　data　analysis　at　the　fatigue　initiation　position　as　typical　evidence　of　fretting　wear.　The　stress　distribution　on　the　blade　in　normal　service　was　calculated　with　a　non-linear　elastic-plastic　finite　element　method.　The　analysis　results　show　that　the　crack　initiation　location　was　different　with　the　location　of　the　highest　Mises　stress.　The　fretting　fatigue　crack　initiated　under　a　combination　of　fretting　wear　and　relatively　high　Mises　stress.　Designed　fretting　fatigue　experiments　were　performed　with　the　results　that　the　fatigue　life　was　greatly　reduced　by　the　interaction　of　the　loading　history　and　local　fretting　wear.　©　2014　Elsevier　Ltd.