My PhD research is part of the UU-TNO salt program. I will focus on developing a 3D numerical modelling tool for single and multi-cavern systems incorporating UU laws developed under this program for salt creep at model mesh scale. The developed model will be calibrated and validated against field data. Finally I will apply the model to a multi-cavern system for hydrogen storage, long-term cavern abandonment and shut-in strategies for both brine production and storage caverns. Additionally, I will conduct a sensitivity analysis to assess the relative impact of geological, rheological, operational, and numerical factors on cavern convergence and subsidence.