Tritium diffusive transport parameters and trapping effects in the reduced activating martensitic steel OPTIFER-IVb

• Published in: Journal of nuclear materials 2000-09, Vol.281 (1), p.34-41
• Main Authors: Esteban, G.A., Perujo, A., Douglas, K., Sedano, L.A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Controled nuclear fusion plants; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Installations for energy generation and conversion: thermal and electrical energy
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/S0022-3115(00)00188-4

A time-dependent gas-phase isovolumetric desorption technique has been used to obtain the hydrogen isotopes transport parameters between 423 and 892 K and driving pressures ranging from 4×10 4 to 1×10 5 Pa. For protium and deuterium the properties diffusivity ( D), Sieverts’ constant ( K s), permeability ( Φ), trapping energy ( E t) and the trap sites concentration ( N t) are given. On the basis of ideal harmonic vibration of the hydrogen isotope atoms in a unique type of solution site, the values derived for the characteristic protium oscillation temperatures are: θ=1884 K, θ *=2387 K. These values lead to the following extrapolated tritium transport parameters: D ( m 2 s −1)=4.166×10 −8 exp (−12 027/RT), K s ( mol m −3 Pa −1/2)=0.271 exp (−27 905/RT) , Φ ( mol m −1 Pa −1/2 s −1)=1.127×10 −8 exp (−39 933/RT), E t ( J/ mol)=55 554, and N t ( sites/ m 3)=0.79×10 24 . The dynamics of the hydrogen isotopes transport and the origin of the trapping phenomenon are discussed in connection with the OPTIFER-IVb microstructure.