Tritium permeation from breeder material to the Water Coolant System (WCS) in Water Cooled Lithium Lead (WCLL) Breeding Blanket (BB) is one of the technological issues to be solved in the design of the European DEMO. Since the tritium extraction from the Water Coolant System is more challenging and expensive than the extraction from the eutectic alloy PbLi, it is mandatory to use of a protective coating on the blanket wall to minimize the permeation rate. Moreover, a protective coating can prevent the corrosion of EUROFER steel by the action of PbLi.

alumina-based coatings are considered as reference for barriers thanks to their good chemical compatibility with the PbLi alloy and their capability to reduce permeation. Three coating technologies were selected in the frame of the EUROfusion project: electrochemical ECX (chemical deposition) process, Pulsed Laser Deposition (PLD) and Atomic Layer Deposition (ALD) coating. The coatings were developed and optimized in order to satisfy the design requirements of good mechanical compatibility with steels, strong adhesion, corrosion compatibility in PbLi at relevant BB design conditions and a Permeation Reduction Factor at least of 200 under neutron irradiation. The present paper aims to describe the status of the technologies and the main results obtained.

The final objectives of the R&D activities are to demonstrate the applicability of the coating to WCLL BB and therefore the scale-up of the technologies from laboratory scale to the BB scale.

breed从育种材料渗透到水冷锂铅（WCLL）繁殖毯（BB）中的水冷却系统（WCS）是欧洲DEMO设计中要解决的技术问题之一。由于从水冷却剂系统中提取t比从低共熔合金PbLi中提取更具挑战性和昂贵，因此必须在毯壁上使用保护性涂层以最大程度地降低渗透率。此外，保护涂层可以通过PbLi的作用来防止EUROFER钢的腐蚀。

氧化铝基涂料与PbLi合金具有良好的化学相容性，并具有减少渗透的能力，因此被认为是阻隔材料的参考。在EUROfusion项目的框架中选择了三种涂层技术：电化学ECX（化学沉积）工艺，脉冲激光沉积（PLD）和原子层沉积（ALD）涂层。开发并优化了涂层，以满足以下设计要求：与钢具有良好的机械相容性，牢固的附着力，在相关的BB设计条件下在PbLi中的腐蚀相容性以及在中子辐照下的渗透减少系数至少为200。本文旨在描述技术的现状和获得的主要成果。

研发活动的最终目标是证明涂料对WCLL BB的适用性，并由此证明技术从实验室规模到BB规模的扩大。