Thermal desorption spectroscopy of W-Ta alloys, exposed to high-flux deuterium plasma

Thermal desorption spectroscopy (TDS) of W-1% Ta and W-5% Ta alloys exposed to a high-flux deuterium plasma (similar to 10(24) m(-2) s(-1)) has been performed. The single peak of the TDS spectra suggests the presence of only one type of trap in these alloys. Simulations using the diffusion code TMAP7 demonstrated that the trapping energies are in the range 0.89-0.96 eV, which suggests the trapping on vacancies as a predominant trapping mechanism in W-Ta alloys. The flux dependence of deuterium retention in W-Ta alloys was determined in the flux range 10(21)-10(24) m(-2) s(-1), with retention decreasing significantly for higher fluxes (while the fluence is kept constant). The obtained data demonstrate that W-Ta alloy does not exhibit blistering under the investigated conditions.