A calculation of the neutron endurance for Al2O3/SS316L

초록

The structural materials of a test blanket module were exposed to neutron irradiation and hydrogen isotope permeation. A quantification of neutron irradiation damage of these materials is important to estimate the point defect rate, which traps hydrogen isotope. To evaluate the structural stability of the hydrogen isotope permeation barrier for international thermonuclear experimental reactor materials, neutron irradiation damage of Al2O3/SS316L is required. An MC-50 cyclotron was used as a source for neutron irradiation during the neutron dose experiments. Beryllium (Be) was used as a target for the neutron generation by Be-9(p,n)B-9 reaction, and the neutron spectrum was calculated. The resultant dominant relative neutron fluxes were similar, with neutron energies of 2.45 and 14.1 MeV, which are given by D-D and D-T reaction from a nuclear fusion reactor. To quantify the extent of damage due to the neutron irradiation, the displacement per atom rate was calculated using the particle and heavy ion transport code system. The effect of the thickness of the Al2O3 layer on the neutron irradiation damage and on its radionuclides was also analyzed. The information on the reaction rate and the radionuclides for charged particles can be combined with a density functional theory analysis to explain the correlation between hydrogen isotope permeability and defects.

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