During thermal-neutron irradiation, Frenkel defects are produced in CdTe due to the recoil of 114Cd following radiative capture by 113Cd. The properties of these defects can be studied by measuring the Hall effect and electrical conductivity before and after successive irradiations. The results indicate that the cadmium vacancy is responsible for electron removal in n-type CdTe and that the introduction rate of cadmium vacancies is strongly influenced by annealing during irradiation.