DESIGN, OPTIMIZATION AND PERFORMANCE TESTING OF SELF-HEALING TRITIUM PERMEATION BARRIERS

Tritium permeation barriers (TPBs) are essential to reduce the tritium permeation through blanket structural materials and cooling tubes. The pores and cracks are the most important problem of thermally sprayed TPBs. Irradiation swelling is another serious problem in NiAl which used as adhesive layer in traditional Al2O3 coatings. A self-healing coating TiC+mixture(TiC/Al2O3)+Al2O3 without NiAl had been designed and manufactured by our group. It can cure 90% porosity after a certain heat treatment under normal atmosphere. The adhesive strength is as good as the traditional coating NiAl+Al2O3. The thermal shock cycles were 300, 210 and 123 at 600 degrees C, 700 degrees C and 800 degrees C respectively. On the basis, the self-healing treatment parameters were explored further, and a more effective and efficient treatment was found. Structural design and component design were also researched. The thermal shock results showed that the thicknesses of TiC layer and mixture (TiC/Al2O3) layer both had a significant effect while the Al2O3 layer hadn't. The interface of TiC and mixture (TiC/Al2O3) was most easily damaged, so other proportion of TiC and Al2O3 was applied, and several kinds of new coatings were designed, manufactured and tested. A better coating has been found, and it will probably be a good candidate for TPBs in fusion reactors.