Given the undeniable climate change caused by global warming, decreasing the carbon footprint by using alternative energy sources became necessary. Thermonuclear fusion energy is one of the strongest candidates when it comes to alternative energy sources since it is safe, has negligible carbon footprint and its yield is incomparable to any other alternative. Credential as fusion performance may be; feasibility and economic attractiveness are something to be considered. The next stage fusion reactors are called DEMOnstration (DEMO) and are being assessed by various sources in terms of performance. In this work, DEMO fusion reactors are to be reviewed and their specifications are to be analyzed in terms of feasibility, while demonstrating how the tritium fueling stage not only presents a challenge for calculating fusion power costs, but also that fusion energy requires further R&D before it can be integrated into the power grid.
Keywords: thermonuclear fusion, DEMO, TBR.