A continuum multi-physics model for the study of hydrogen cryogenic desublimation in ITER Disruption Mitigation System

A continuum three dimensional multi-physics model is introduced, both on axial-symmetric and three-dimensional domains, for studying the hydrogen pellet formation in the ITER Disruption Mitigation System. It accurately describes the pellet formation by direct gas to solid phase transition (desublimation). Conjugate heat transfer analysis is applied, and an enthalpy method accounting for the density jump at transition interface is developed. The newly introduced model is firstly validated against experimental results coming from prototype devices, and then applied to the study of pellet formation process by desublimation in one of the test setups of the ITER DMS system. Numerical predictions are in good agreement with experimental results, and some recommendations to optimize the operating conditions of ITER DMS system are given.