Nuclear　fuel　cladding　is　subjected　to　neutron　irradiation　in　a　high-Temperature　stress　environment,　and　the　structural　integrity　of　the　cladding　is　very　important　for　the　safe　operation　of　nuclear　reactors.　FeCrAl　alloy　has　become　a　promising　candidate　cladding　material　for　the　accident　tolerance　fuel　development　in　view　of　its　excellent　irradiation　resistance　and　high　temperature　strength.　This　work　aims　to　study　the　creep　properties　of　FeCrAl　alloy　at　high　temperatures　under　neutron　irradiation.　Thermal　and　irradiation　creep　behavior　in　nanocrystalline　FeCrAl　samples　is　examined　using　molecular　dynamics　simulation　method.　And　the　effects　of　temperature,　stress,　irradiation　dose　rate　on　the　creep　rate　and　parameters　of　the　creep　constitutive　equations　are　discussed.　The　results　show　that　the　thermal　creep　rate　is　greater　than　irradiation　creep　rate.　The　effect　of　temperature　on　the　thermal　creep　stress　exponent　is　relatively　small　at　low　stress,　but　is　obvious　when　stress　exceeds　0.8　GPa.　The　higher　the　temperature,　the　larger　the　thermal　creep　stress　exponent.　The　irradiation　creep　rate　increases　almost　linearly　with　the　dose　rate,　that　is,　the　exponent　of　dose　rate　for　irradiation　creep　approach　1.0.　Irradiation　creep　stress　exponent　fluctuates　very　little　around　1.1　within　the　scope　of　the　present　research.　Besides,　higher　temperature　accelerates　the　linear　increase　of　irradiation　creep　rate　with　dose　rate,　and　the　irradiation　creep　pre-factor　becomes　higher.　©　2022　American　Society　of　Mechanical　Engineers　(ASME).　All　rights　reserved.