Tritium barrier development for austenitic stainless steel by its aluminizing in a lithium melt

Abstract

A technique for obtaining coatings on a 0.12%C/18%Cr/10%Ni/Ti austenitic stainless steel by its aluminizing in melts of the following composition x%Al+(100%− x)%Li( x=3, 10) at the temperature range 870–1070 K for 5–100 h has been developed. An investigation in to the decrease in the tritium penetration through the steel has been carried out. It has been shown that two-side aluminizing of the steel in the 10%Al/90%Li melt at 870 and 970 K for 5 h decreases its tritium permeability by more than three orders of magnitude. Furthermore, aluminizing the steel under these regimes reduces its erosion coefficient by one order of magnitude on average due to radiation blistering, decreases its coefficient of physical sputtering by more than 2.5 times and protects the steel from failure under the action of hydrogen pulsed plasma fluxes with the incident flux specific power up to 4–5·10 10 W m −2 and a pulse duration of 10–50 μs. The mechanisms of decreasing the tritium permeation with regard to the surface relief forming under the treatment have been discussed.