[en] Automatic translation: Test objective and justification for specimen specification BR2-P14 / P16 is the first series of irradiation experiments within German HTR fuel element development, in which coated fuel particles of the burn-up (feed) type up to a burn-up of 70% fima and up to one Dose of fast neutrons (E> 0.1 MeV) of 8 * 10²¹ cm^-2 are irradiated must. These experiments are intended to provide initial information about the most suitable fuel core type for the high requirements. Besides Results are expected on the question of how much the fuel core diameter of the individual types affects the irradiation behavior of the burned-up particles influenced. This is why some of the particles are used in coupons, in each of which about 60 particles can be examined individually, their core have different sizes due to the production-related distribution of diameters (about 100 µm).