To　accurately　assess　the　in-pile　performance　of　the　accident　tolerant　fuel　(ATF)　over　the　whole　life　for　the　light　water　reactors　(LWR),　a　full　coupling　of　neutronics/thermal-hydraulics/fuel-performance　is　needed.　In　this　paper,　a　multiphysics　coupling　code　system　named　NECP-CLAMPERL　is　developed　based　on　the　high-fidelity　neutronics　code　NECP-X,　the　sub-channel　thermal-hydraulics　code　CTF,　the　finite-element　fuel　performance　code　NECP-CALF　and　the　multiphysics　object-oriented　simulation　environment　(MOOSE).　The　code　system　is　then　applied　to　evaluate　the　performance　of　U3Si2　fuel,　one　of　the　most　promising　ATFs,　by　simulating　a　typical　fuel　assembly　in　pressurized　water-cooled　reactors　(PWR).　The　quantities　of　interest　including　the　reactivity,　power　distribution,　fuel　temperature,　clad　stress,　fission　gas　release,　plenum　pressure,　fuel　radial　displacement,　gap　width　and　PCMI　are　presented　and　analyzed　in　comparison　with　the　traditional　UO2　fuel.　Future　works　and　other　potential　applications　are　also　identified.　©　2021　Elsevier　Ltd