Abstract Study of the Phebus FPT-1 experiment with MELCOR 2.2.11932 severe accident integral computer code is presented. The developed model and simulations cover the fuel bundle phase up to 20,000 s after the test initiation. The paper is focused on the assessment of material released from the bundle with emphasis on radioactive releases. The core degradation, thermal-hydraulics, hydrogen production and structural material releases are also studied as coupled phenomena. Simulations are compared with experimental results and selected solutions available in the literature. Parametric sensitivity calculations were performed for selected modelling parameters influencing releases. Especially, the CORSOR-Booth model revisions are compared and assessed. Radioactive releases for MELCOR 2.1 and 2.2 are compared. New modelling parameters for molybdenum and Ag-In-Cd released as pseudo fission products are presented. A satisfactory agreement was obtained, confirming the validity of the developed model and efficiency of the new MELCOR2.2 code for the FPT-1 test.