Actively cooled plasma facing components in Tore Supra: From material and design to operation

In current fusion devices, the components located in front of plasma, the so-called plasma facing components (PFCs), need to sustain severe constraints such as high thermal flux (several MW m−2), erosion and flux of particles. Feedback from these challenging components is essential for the success of the next generation of components, in particular in term of manufacturing or handling intense heat loads. Tore Supra actively cooled high heat flux PFCs are able to sustain up to 10 MW m−2 during long plasma pulses. They are at present the only ones in operation in a fusion device. They are described in details from design (including the testing programme used for concept validation) to operation. Lessons learned from the industrialization programme, which could be essential for ITER, will be presented. Finally, the experimental feedback with actively cooled walls, including in situ monitoring to guarantee plasma facing component safety, will be summarized. Another very important feature has been noticed, namely the in vessel progressive uptake of hydrogen, a likely source of concern for ITER.