Applications of high temperature superconducting tapes in radiation environments, in particular magnets for fusion or high-energy physics, have become of increasing interest in recent years. Neutron radiation frequently exerts the most deleterious effects on the material in these applications; hence an understanding of the created defects and their relevance for the observed changes is vital for guiding the design of conductors and magnets. High-energy neutrons are known to produce defects of a few nanometres in size as observed by transmission electron microscopy. These defects are efficient pinning centers, and therefore can enhance the critical currents in the superconductor significantly. However, less is known about the introduced smaller defects. Any defects increase scattering of charge carriers which breaks cooper pairs in high temperature superconductors and reduces both, the transition temperature and the density of superconducting charge carriers. The latter counteracts the beneficial effect of increased flux pinning and eventually leads to a degradation of the critical currents. Neutron irradiation experiments were performed in the TRIGA-Mark II reactor in Vienna. The relation between the observed changes of resistivity, mobility and density of charge carriers with the superconducting properties, namely transition temperature, superfluid density and critical current will be discussed. The most relevant defects for the degradation of the properties are likely too small to be observed by electron microscopy. Single displaced atoms in the copper oxygen planes seem to be most efficient for scattering charge carriers in cuprate superconductors and hence responsible for the decrease of the critical current in coated conductors exposed to high fluences of neutrons. On the other hand, they were also found to contribute to flux pinning at low temperatures.