Speaker
Vladimir Khripunov
(Fusion Reactor Department)
Description
Primary radiation damage (atomic displacements) and Helium and Hydrogen production rates in plasma facing components (PFCs) of a fusion system are usually determined by the high energy parts of neutron spectra formed in plasma chamber from the initial fusion neutron source. According to presented estimates, the energetic alphas and protons, appearing in PFC materials in the (n,a) and (n,p) threshold reactions, may cause additional, secondary material damage increasing damage from neutrons by a factor of 2-4. An additional Helium production is expected in systems with a soft neutron spectrum in case of using W- or an W-alloy as an armor attached to the first wall. Calculations show that Re and Os as transmutation products appeared in W under long term neutron irradiation account for a source of intensive helium production in (n,a) reactions with these secondary radionuclides. These even if preliminary estimated radiation effects should be taken into account in new material considerations for long term concepts.
Co-author
Vladimir Khripunov
(Fusion Reactor Department, National Research Centre "Kurchatov Institute", Moscow, Russian Federation)
