To　analyze　the　rapid　change　of　Pressurized　Water　Reactor　(PWR)　core　states　in　the　time　scale　of　seconds,　a　transient　analysis　code　named　Bamboo-Transient　has　been　developed　to　provide　neutronics　and　thermal-hydraulics　coupled　simulation　with　distinguished　prompt　and　delayed　neutrons.　These　transient　processes　can　be　initialized　by　control　rod　movements,　core　inlet　coolant　temperature　perturbation　and/or　inlet　coolant　flow　perturbation.　Different　from　the　existing　codes,　it　adopts　the　Predictor-Corrector　Improved　Quasi-Static　Method　(PC-IQS)　to　ensure　the　computational　efficiency,　and　employs　the　heterogeneous　Variational　Nodal　Method　as　its　three-dimensional　neutron　diffusion　solver.　Three　advantages　can　be　provided　by　HetVNM　due　to　the　elimination　of　the　transverse　integration　approximation.　Firstly,　control　rod　cusping　effect　can　be　eliminated　by　directly　treating　heterogeneous　cross　sections　and　discontinuity　factors.　Secondly,　physical　adjoint　neutron　flux　can　also　be　obtained　by　constructing　and　solving　the　multi-group　adjoint　equations　with　discontinuous　factors.　Thirdly,　the　detailed　nodal　precursor　density　distribution　can　be　directly　provided　by　the　detailed　nodal　fluxes　from　VNM　to　ensure　the　kinetics　calculation　accuracy.　In　this　paper,　these　methods　and　the　Bamboo-Transient　code　were　verified　by　the　NEACRP　rod　ejection　accident　and　uncontrolled　control　rod　withdraw　accident　in　BEAVRS　reactor　core.　©　2019　Elsevier　B.V.