Development of tritium permeation barriers on Al base in Europe

The development of the water cooled lithium lead (WCLL) DEMO fusion reactor requires the production of a material capable of acting as a tritium perme ation barrier (TPB), In the DEMO blanket reactor permeation barriers on the structural material are required to reduce the tritium permeation from the Pb-17Li or the plasma into the cooling water to acceptable levels (<1 g/d) . Because of experimental work previously performed, one of the most promis ing TPB candidates is Al base coatings. Within the EU a large R&D programme is in progress to develop a TPB fabrication technique, compatible with the structural materials requirements and capable of producing coatings with a cceptable performances. The research is focused on chemical vapour depositi on (CVD), hot dipping, hot isostatic pressing (HIP) technology and spray (t his one developed also for repair) deposition techniques. The final goal is to select a reference technique to be used in the blanket of the DEMO reac tor and in the ITER test module fabrication. The activities performed in fo ur European laboratories are summarised here. (C) 1999 Elsevier Science B.V . All rights reserved.