ITER, the largest magnetic fusion reactor so far, is currently under construction and is expected to produce its first plasma in 2025. It will explore the regime of a burning plasma, the condition necessary for net electricity production, but the reaction will only be partly self-sustained. In order to demonstrate a fully self-sustained burning plasma, the aptly named DEMO reactor is planned. However, ITER is already pushing the limits of conventional technology to handle the heat flux at the most critical region called the divertor. The DEMO reactor will double that heat flux, and conventional methods are not expected to provide adequate protection. A 3D-printed heat pipe array is proposed to protect the DEMO divertor from the burning plasma. This talk will describe the proposal and the results obtained from initial experiments.