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Received 19 October 2022, Revised 11 December 2022, Accepted 27 December 2022, Available online 13 January 2023, Version of Record 13 January 2023, The aim is to provide an assessment of radiation damage in coated films on refractive substrates that could be used as relevant information to protect the field lenses in optical diagnostics for ITER. Radiation-resistant optical materials with transparent properties should transfer light from plasma to detectors through the interspace until the port cell area where they are located (more than 10 m from the vacuum window). These optical coatings and substrates should have resilience enough to withstand neutron and gamma irradiation without significant degradation of their transmittance. Coated sapphire (Al2O3 windows), YAG with Broad Band Anti-Reflective (BBAR) and substrates of BaF2/CaF2 protected with anti-humidity coating (Parylene-C) were extensively tested. After testing, transmission mea- surements and analysis of optical surfaces yield significant discoveries. All substrates showed good refractive performance under gamma radiation. On the contrary, Parylene-C did not resist temperatures above 100 degrees Celsius as expected, according to manufacturing specifications. In addition, it was observed that with an energy dose of 332 kGy of gamma rays and a significantly lower temperature of 50 degrees Celsius, the Parylene-C protection is also damaged. Coated sapphire had the best overall performance with respect to the neutron irradiation tests. Nevertheless, the decrease in transmission observed in the YAG and BaF2 coated samples is not significant for the expected cumulative neutron dose that these samples will receive at their location within the diagnostic. This information was considered for the selection of the best candidates as refractive lenses and optical coatings for the Preliminary Design Review (PDR) of ex-vessel components that will integrate the Wide-Angle Viewing System (WAVS) for ITER Equatorial Port 12., Fusion for Energy, Sección Deptal. de Óptica (Óptica), Fac. de Óptica y Optometría, TRUE, pub

The present paper studies the corrosion behavior of several sputtered coatings (nanostructured W, SiC and Al2O3) under the working conditions expected for the helium cooled pebbles bed breeder concept to be used in future nuclear fusion reactors. To this purpose, coatings were evaluated during 240 h at a temperature of 550 °C in Helium atmosphere with 120 ppms of water to simulate the purge gas in the presence of ceramic pebbles whose composition was a mixture of lithium silicate/titanate. The 3-D topography, morphology, microstructure and elemental composition of the coatings were studied prior to and after the corrosion tests. Results evidence that coatings show quite different corrosion behavior: Because of oxidation, nW is completely ruled out for such application, the corrosion behavior of Al2O3 coating is questionable whereas, SiC coating is shown to act as a real corrosion barrier. Nanoscratch measurements of this last coating show that it also has a good adhesion to the Eurofer substrate both prior to and after the corrosion test.