Divertor,　one　of　the　most　challenging　in-vessel　components　facing　to　plasma　in　a　Tokamak　device,　is　composed　of　tungsten　or　carbon　fiber　composites　(CFC)　mono-block　of　multilayer　tube　structure　to　withstand　huge　heat　and　particle　flux.　The　multilayer　tube　bonded　with　hot　isostatic　pressing　(HIP)　welding　technology　is　one　of　the　key　components　for　removing　heat　in　divertor.　The　debonding　defect　in　HIP　welding　surface　may　occurs　due　to　fabrication　and　heat　fatigue　reason　and　may　significantly　reduce　the　heat　transfer　ability　of　the　tubes.　The　debonding　defect　needs　to　be　inspected　in　a　nondestructive　way　to　prevent　local　over　heat　and　structural　failure.　In　this　paper,　two　kinds　of　EMAT　probes　are　proposed　to　detect　debonding　defect　in　the　multilayer　tubes　and　their　validity　is　valuated　numerically　by　using　a　simulation　code　based　on　the　formulation　of　reduce　vector　potential　(Ar)　method　and　the　time　domain　difference　scheme　for　wave　propagation　simulation.