In　this　study,　uncertainty　analysis　has　been　performed　to　the　time-dependent　transient　simulation　of　the　C5G7-TD　benchmark　problem,　propagating　the　nuclear-data　uncertainties　to　the　key　parameters　of　interest.　The　detailed　material　compositions　and　geometries　of　C5G7-TD　have　been　applied　for　the　time-dependent　transient　simulation.　For　uncertainty　analysis　of　the　transient　simulation,　multigroup　cross-section　covariance　library　has　been　generated　based　on　ENDF/B-VII.1　using　the　NJOY　code.　Our　home-developed　uncertainty-analysis　code　named　UNICORN　has　been　utilized　for　the　uncertainty　analysis,　using　the　statistical　sampling　method.　For　the　steady-state　and　transient　simulations,　our　home-developed　high-fidelity　neutronics　code　NECP-X　has　been　utilized.　The　relative　uncertainties　of　the　fuel-assembly　normalized　power　and　pin-wise　power　have　been　quantified　as　function　of　time.　The　numerical　results　show　that　the　maximum　relative　uncertainties　for　the　assembly　normalized　power　can　up　to　be　about　2.14%　and　the　value　for　the　pin-wise　power　distributions　can　be　about　3.54%.　©　2019　Elsevier　Ltd