The ingenious FAIDUS (Fuel Assembly Inner DUct Structure) design is conceptualized to deliver inherent safety in case of local fuel melting through extended melt discharge out of the core to avoid large-scale pool formation. Towards this, EAGLE experimental project is pursued by Japan Atomic Energy Agency to assess the effectiveness of FAIDUS concept in mitigating the accident. The test data suggested that early failure of the duct wall confers a large escape path for intended fuel discharge out of the core, terminating the accident primordially. The post-test analysis deduced that the premature wall failure is initiated by the high heat flux from the melt pool on account of molten steel existence in the pool. The present work investigates the thermal damage characteristic of duct wall following the melt pool formation, including melt pool dynamics and crust formation behavior. The mechanism of effective heat exchange between molten pool to duct wall in ID1 test is examined. The simulation results predict that the enhancement in heat transfer due to presence of molten steel in the melt pool imparts a large thermal load on the duct wall resulting in its immediate failure.