Evaluation of deuterium permeation reduction factor of various coatings deposited on ferritic/martensitic steels for development of tritium permeation barrier

Evaluation of tritium permeation reduction performance of various coatings such as amorphous CrPO4, plasma sprayed zirconium oxide ZrO2 and gold plating was examined by means of deuterium permeation experiment and thermal stress analysis. As the results, ZrO2 showed relatively good permeation reduction performance about 1/10, and results indicated that deuterium permeates through the grain boundaries and/or cracks formed in the ZrO2 coating. Improvement such as filling diffusion paths will be effective for further permeation reduction performance. On the other hand, gold plating showed excellent permeation reduction performance around 550 K. Permeation reduction by gold plating would be attributed to low solubility of deuterium in gold. Additionally, results of thermal stress analysis were consistent with the results of permeation experiment. Therefore, thermal stress analysis could be an effective method for the selecting permeation reduction coatings prior to the permeation experiment.