Role of radiation in vapor shielding of first wall during disruption

Abstract

An initially ablated vapor may provide an important radiation shield to reduce the heat load and the further ablation of the Be divertor strike plate during an ITER disruption. Thus, we investigate the role of line emission in Be at relevant temperatures and densities. For an ion density of 10 18 cm −3 (10 24 m −3), we calculate that there is significant line emission and re-absorption in the temperature range from 3 to 10 eV. The re-absorption limits the line emission that strikes the plate. Line transfer calculations coupled with detailed atomic modeling predict that lines contribute 10–50% of the impinging plate radiation. We note that because of this effect, previous calculations using multi-group radiation transfer may under-estimate the vapor shielding for these ITER-relevant parameters.