During edge localised modes (ELMs) high heat fluxes are incident on divertor targets, which future fusion devices will not withstand [1]. A solution to reduce the heat fluxes could be the new Super-X divertor, which will be tested on the MAST-U tokamak. The divertor has an increased connection length, magnetic flux expansion and is designed to retain neutrals for divertor heat-flux mitigation [2]. Predictions of the effect on ELMs in the new magnetic configuration are made using the nonlinear MHD code JOREK [3], which is being actively validated [4]. Using the JOREK neutrals model [5] detachment has been observed and ELM burn-through has been simulated. During the ELM plasma ionises the neutrals front (fig. 1), the target temperature and heat flux increase and then significantly decrease 1.5 ms  after the ELM crash. The peak heat flux to the outer target due to the ELM is 2 MW/m², which is low in comparison to previous MAST type-I ELM H-mode experiments. A study of ELM burn-through in the new Super-X configuration is performed; the role of neutral pressure in the divertor is analysed. The simulations are based on validation against MAST data and the neutrals model is benchmarked to SOLPS [6].