As a next-step in the tokamak-based fusion programme, the DEMO fusion reactor is foreseen to produce relevant output electricity, in the order of ∼500 MW delivered to the network. The scenarios that are being presently investigated consist of a pulsed device, called DEMO1, and a steady-state device, called DEMO2. In this work, which is focused on the pulsed device DEMO1, scenarios are studied from the point of view of core transport, to assess plasma performance and limitations due to core microinstabilities. The role of radiated power, aspect ratio, and height of temperature pedestal are assessed as they impact both core energy and particle transport. Open issues in this framework are also discussed.