Abstract
In connection with the IAEA-neutron seed irradiation Programme, a standard neutron irradiation facility has been constructed. The application of solid state track recorders for fast neutron spectra measurements inside this facility is discussed. Fissionable targets of 235U, 239Pu, 237Np, 238W and 232Th will be used, an approximative solution for the incident neutron spectrum will be obtained by a five-group method.